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Deshler T, Luo B, Kovilakam M, Peter T, Kalnajs LE. Retrieval of Aerosol Size Distributions From In Situ Particle Counter Measurements: Instrument Counting Efficiency and Comparisons With Satellite Measurements. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:5058-5087. [PMID: 31245233 PMCID: PMC6582618 DOI: 10.1029/2018jd029558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 04/08/2019] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
The method to derive aerosol size distributions from in situ stratospheric measurements from the University of Wyoming is modified to include an explicit counting efficiency function (CEF) to describe the channel-dependent instrument counting efficiency. This is motivated by Kovilakam and Deshler's (2015, https://doi.org/10.1002/2015JD023303) discovery of an error in the calibration method applied to the optical particle counter (OPC40) developed in the late 1980s and used from 1991 to 2012. The method can be applied to other optical aerosol instruments for which counting efficiencies have been measured. The CEF employed is the integral of the Gaussian distribution representing the instrument response at any one aerosol channel, the aerosol counting efficiency. Results using the CEF are compared to previous derivations of aerosol size distributions (Deshler et al., 2003, https://doi.org/10.1029/2002JD002514) applied to the measurements before and after Kovilakam and Deshler's correction of number concentration for the OPC40 calibration error. The CEF method is found, without any tuning parameter, to reproduce or improve upon the Kovilakam and Deshler's results, thus accounting for the calibration error without any external comparisons other than the laboratory determined counting efficiency at each aerosol channel. Moments of the new aerosol size distributions compare well with aerosol extinctions measured by Stratospheric Aerosol and Gas Experiment II and Halogen Occultation Experiment in the volcanic period 1991-1996, generally within ±40%, the precision of OPC40 moments, and in the nonvolcanic period after 1996, generally within ±20%. Stratospheric Aerosol and Gas Experiment II and Halogen Occultation Experiment estimates of aerosol surface area are generally in agreement with those derived using the new CEF method.
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Affiliation(s)
- Terry Deshler
- Department of Atmospheric ScienceUniversity of WyomingLaramieWYUSA
- Laboratory for Atmospheric and Space PhysicsBoulderCOUSA
| | - Beiping Luo
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | - Mahesh Kovilakam
- Department of Atmospheric ScienceUniversity of WyomingLaramieWYUSA
- NASA Langley Research CenterHamptonVAUSA
| | - Thomas Peter
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
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2
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Stable Water Isotopologues in the Stratosphere Retrieved from Odin/SMR Measurements. REMOTE SENSING 2018. [DOI: 10.3390/rs10020166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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3
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Hurst DF, Read WG, Vömel H, Selkirk HB, Rosenlof KH, Davis SM, Hall EG, Jordan AF, Oltmans SJ. Recent divergences in stratospheric water vapor measurements by frost point hygrometers and the Aura Microwave Limb Sounder. ATMOSPHERIC MEASUREMENT TECHNIQUES 2016; 9:4447-4457. [PMID: 28966694 PMCID: PMC5619251 DOI: 10.5194/amt-9-4447-2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Balloon-borne frost point hygrometers (FPs) and the Aura Microwave Limb Sounder (MLS) provide high-quality vertical profile measurements of water vapor in the upper troposphere and lower stratosphere (UTLS). A previous comparison of stratospheric water vapor measurements by FPs and MLS over three sites - Boulder, Colorado (40.0° N); Hilo, Hawaii (19.7° N); and Lauder, New Zealand (45.0° S) - from August 2004 through December 2012 not only demonstrated agreement better than 1% between 68 and 26 hPa but also exposed statistically significant biases of 2 to 10% at 83 and 100 hPa (Hurst et al., 2014). A simple linear regression analysis of the FP-MLS differences revealed no significant long-term drifts between the two instruments. Here we extend the drift comparison to mid-2015 and add two FP sites - Lindenberg, Germany (52.2° N), and San José, Costa Rica (10.0° N) - that employ FPs of different manufacture and calibration for their water vapor soundings. The extended comparison period reveals that stratospheric FP and MLS measurements over four of the five sites have diverged at rates of 0.03 to 0.07 ppmv year-1 (0.6 to 1.5% year-1) from ~2010 to mid-2015. These rates are similar in magnitude to the 30-year (1980-2010) average growth rate of stratospheric water vapor (~ 1% year-1) measured by FPs over Boulder (Hurst et al., 2011). By mid-2015, the FP-MLS differences at some sites were large enough to exceed the combined accuracy estimates of the FP and MLS measurements.
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Affiliation(s)
- Dale F. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - William G. Read
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Holger Vömel
- Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Henry B. Selkirk
- Laboratory for Atmospheric Chemistry and Dynamics, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- Goddard Earth Science Technology and Research, Universities Space Research Association, Columbia, Maryland, USA
| | - Karen H. Rosenlof
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Sean M. Davis
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Emrys G. Hall
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Allen F. Jordan
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Samuel J. Oltmans
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
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4
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Kräuchi A, Philipona R, Romanens G, Hurst DF, Hall EG, Jordan AF. Controlled weather balloon ascents and descents for atmospheric research and climate monitoring. ATMOSPHERIC MEASUREMENT TECHNIQUES 2016; 9:929-938. [PMID: 29263765 PMCID: PMC5734649 DOI: 10.5194/amt-9-929-2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In situ upper-air measurements are often made with instruments attached to weather balloons launched at the surface and lifted into the stratosphere. Present-day balloon-borne sensors allow near-continuous measurements from the Earth's surface to about 35 km (3-5 hPa), where the balloons burst and their instrument payloads descend with parachutes. It has been demonstrated that ascending weather balloons can perturb the air measured by very sensitive humidity and temperature sensors trailing behind them, particularly in the upper troposphere and lower stratosphere (UTLS). The use of controlled balloon descent for such measurements has therefore been investigated and is described here. We distinguish between the single balloon technique that uses a simple automatic valve system to release helium from the balloon at a preset ambient pressure, and the double balloon technique that uses a carrier balloon to lift the payload and a parachute balloon to control the descent of instruments after the carrier balloon is released at preset altitude. The automatic valve technique has been used for several decades for water vapor soundings with frost point hygrometers, whereas the double balloon technique has recently been re-established and deployed to measure radiation and temperature profiles through the atmosphere. Double balloon soundings also strongly reduce pendulum motion of the payload, stabilizing radiation instruments during ascent. We present the flight characteristics of these two ballooning techniques and compare the quality of temperature and humidity measurements made during ascent and descent.
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Affiliation(s)
- Andreas Kräuchi
- Institute for Atmospheric and Climate Science, ETH Zurich, 8057 Zurich, Switzerland
| | - Rolf Philipona
- Federal Office of Meteorology and Climatology MeteoSwiss, Aerological Station, 1530 Payerne, Switzerland
| | - Gonzague Romanens
- Federal Office of Meteorology and Climatology MeteoSwiss, Aerological Station, 1530 Payerne, Switzerland
| | - Dale F. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado 80305, USA
| | - Emrys G. Hall
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado 80305, USA
| | - Allen F. Jordan
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado 80305, USA
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5
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Müller R, Kunz A, Hurst DF, Rolf C, Krämer M, Riese M. The need for accurate long-term measurements of water vapor in the upper troposphere and lower stratosphere with global coverage. EARTH'S FUTURE 2016; 4:25-32. [PMID: 29264371 PMCID: PMC5734646 DOI: 10.1002/2015ef000321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water vapor is the most important greenhouse gas in the atmosphere although changes in carbon dioxide constitute the "control knob" for surface temperatures. While the latter fact is well recognized, resulting in extensive space-borne and ground-based measurement programs for carbon dioxide as detailed in the studies by Keeling et al. (1996), Kuze et al. (2009), and Liu et al. (2014), the need for an accurate characterization of the long-term changes in upper tropospheric and lower stratospheric (UTLS) water vapor has not yet resulted in sufficiently extensive long-term international measurement programs (although first steps have been taken). Here, we argue for the implementation of a long-term balloon-borne measurement program for UTLS water vapor covering the entire globe that will likely have to be sustained for hundreds of years.
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Affiliation(s)
- Rolf Müller
- Institute of Energy and Climate Research (IEK-7), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Anne Kunz
- Institute for Atmospheric and Climate Research, ETH Zurich, Zurich, Switzerland
| | - Dale F Hurst
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Christian Rolf
- Institute of Energy and Climate Research (IEK-7), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Martina Krämer
- Institute of Energy and Climate Research (IEK-7), Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Martin Riese
- Institute of Energy and Climate Research (IEK-7), Forschungszentrum Jülich GmbH, Jülich, Germany
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6
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Weigel K, Rozanov A, Azam F, Bramstedt K, Damadeo R, Eichmann KU, Gebhardt C, Hurst D, Kraemer M, Lossow S, Read W, Spelten N, Stiller GP, Walker KA, Weber M, Bovensmann H, Burrows JP. UTLS water vapour from SCIAMACHY limb measurementsV3.01 (2002-2012). ATMOSPHERIC MEASUREMENT TECHNIQUES 2016; 9:133-158. [PMID: 29263764 PMCID: PMC5734655 DOI: 10.5194/amt-9-133-2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements from August 2002 until April 2012. SCIAMACHY measured the scattered or direct sunlight using different observation geometries. The limb viewing geometry allows the retrieval of water vapour at about 10-25 km height from the near-infrared spectral range (1353-1410 nm). These data cover the upper troposphere and lower stratosphere (UTLS), a region in the atmosphere which is of special interest for a variety of dynamical and chemical processes as well as for the radiative forcing. Here, the latest data version of water vapour (V3.01) from SCIAMACHY limb measurements is presented and validated by comparisons with data sets from other satellite and in situ measurements. Considering retrieval tests and the results of these comparisons, the V3.01 data are reliable from about 11 to 23 km and the best results are found in the middle of the profiles between about 14 and 20 km. Above 20 km in the extra tropics V3.01 is drier than all other data sets. Additionally, for altitudes above about 19 km, the vertical resolution of the retrieved profile is not sufficient to resolve signals with a short vertical structure like the tape recorder. Below 14 km, SCIAMACHY water vapour V3.01 is wetter than most collocated data sets, but the high variability of water vapour in the troposphere complicates the comparison. For 14-20 km height, the expected errors from the retrieval and simulations and the mean differences to collocated data sets are usually smaller than 10 % when the resolution of the SCIAMACHY data is taken into account. In general, the temporal changes agree well with collocated data sets except for the Northern Hemisphere extratropical stratosphere, where larger differences are observed. This indicates a possible drift in V3.01 most probably caused by the incomplete treatment of volcanic aerosols in the retrieval. In all other regions a good temporal stability is shown. In the tropical stratosphere an increase in water vapour is found between 2002 and 2012, which is in agreement with other satellite data sets for overlapping time periods.
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Affiliation(s)
- K. Weigel
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - A. Rozanov
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - F. Azam
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - K. Bramstedt
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - R. Damadeo
- NASA Langley Research Center, Hampton, Virginia, USA
| | - K.-U. Eichmann
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - C. Gebhardt
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - D. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - M. Kraemer
- Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research – Stratosphere IEK-7, Jülich, Germany
| | - S. Lossow
- Karlsruhe Institute of Technology – KIT, Institute for Meteorology and Climate Research – IMK, Karlsruhe, Germany
| | - W. Read
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - N. Spelten
- Forschungszentrum Jülich GmbH, Institute for Energy and Climate Research – Stratosphere IEK-7, Jülich, Germany
| | - G. P. Stiller
- Karlsruhe Institute of Technology – KIT, Institute for Meteorology and Climate Research – IMK, Karlsruhe, Germany
| | - K. A. Walker
- Department of Physics, University of Toronto, Toronto, Canada
| | - M. Weber
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - H. Bovensmann
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
| | - J. P. Burrows
- Institute of Environmental Physics – IUP, University of Bremen, Bremen, Germany
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7
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Hall EG, Jordan AF, Hurst DF, Oltmans SJ, Vömel H, Kühnreich B, Ebert V. Advancements, measurement uncertainties, and recent comparisons of the NOAA frost point hygrometer. ATMOSPHERIC MEASUREMENT TECHNIQUES 2016; 9:4295-4310. [PMID: 28845201 PMCID: PMC5571835 DOI: 10.5194/amt-9-4295-2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The NOAA frost point hygrometer (FPH) is a balloon-borne instrument flown monthly at three sites to measure water vapor profiles up to 28 km. The FPH record from Boulder, Colorado, is the longest continuous stratospheric water vapor record. The instrument has an uncertainty in the stratosphere that is < 6 % and up to 12 % in the troposphere. A digital microcontroller version of the instrument improved upon the older versions in 2008 with sunlight filtering, better frost control, and resistance to radio frequency interference (RFI). A new thermistor calibration technique was implemented in 2014, decreasing the uncertainty in the thermistor calibration fit to less than 0.01 °C over the full range of frost - or dew point temperatures (-93 to +20 °C) measured during a profile. Results from multiple water vapor intercomparisons are presented, including the excellent agreement between the NOAA FPH and the direct tunable diode laser absorption spectrometer (dTDLAS) MC-PicT-1.4 during AquaVIT-2 chamber experiments over 6 days that provides confidence in the accuracy of the FPH measurements. Dual instrument flights with two FPHs or an FPH and a cryogenic frost point hygrometer (CFH) also show good agreement when launched on the same balloon. The results from these comparisons demonstrate the high level of accuracy of the NOAA FPH.
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Affiliation(s)
- Emrys G. Hall
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
| | - Allen F. Jordan
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
| | - Dale F. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
| | - Samuel J. Oltmans
- NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, USA
| | - Holger Vömel
- National Center for Atmospheric Research, Earth Observation Laboratory, Boulder, Colorado, USA
| | - Benjamin Kühnreich
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
- Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt, Germany
| | - Volker Ebert
- Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
- Center of Smart Interfaces, Technische Universität Darmstadt, Darmstadt, Germany
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8
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Davis SM, Rosenlof KH, Hassler B, Hurst DF, Read WG, Vömel H, Selkirk H, Fujiwara M, Damadeo R. The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database: a long-term database for climate studies. EARTH SYSTEM SCIENCE DATA 2016; 8:461-490. [PMID: 28966693 PMCID: PMC5619261 DOI: 10.5194/essd-8-461-2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In this paper, we describe the construction of the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database, which includes vertically resolved ozone and water vapor data from a subset of the limb profiling satellite instruments operating since the 1980s. The primary SWOOSH products are zonal-mean monthly-mean time series of water vapor and ozone mixing ratio on pressure levels (12 levels per decade from 316 to 1 hPa). The SWOOSH pressure level products are provided on several independent zonal-mean grids (2.5, 5, and 10°), and additional products include two coarse 3-D griddings (30° long × 10° lat, 20° × 5°) as well as a zonal-mean isentropic product. SWOOSH includes both individual satellite source data as well as a merged data product. A key aspect of the merged product is that the source records are homogenized to account for inter-satellite biases and to minimize artificial jumps in the record. We describe the SWOOSH homogenization process, which involves adjusting the satellite data records to a "reference" satellite using coincident observations during time periods of instrument overlap. The reference satellite is chosen based on the best agreement with independent balloon-based sounding measurements, with the goal of producing a long-term data record that is both homogeneous (i.e., with minimal artificial jumps in time) and accurate (i.e., unbiased). This paper details the choice of reference measurements, homogenization, and gridding process involved in the construction of the combined SWOOSH product and also presents the ancillary information stored in SWOOSH that can be used in future studies of water vapor and ozone variability. Furthermore, a discussion of uncertainties in the combined SWOOSH record is presented, and examples of the SWOOSH record are provided to illustrate its use for studies of ozone and water vapor variability on interannual to decadal timescales. The version 2.5 SWOOSH data are publicly available at doi:10.7289/V5TD9VBX.
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Affiliation(s)
- Sean M. Davis
- NOAA Earth Systems Research Laboratory (ESRL), Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado at Boulder, Boulder, CO, USA
| | | | - Birgit Hassler
- NOAA Earth Systems Research Laboratory (ESRL), Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado at Boulder, Boulder, CO, USA
| | - Dale F. Hurst
- NOAA Earth Systems Research Laboratory (ESRL), Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado at Boulder, Boulder, CO, USA
| | - William G. Read
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Holger Vömel
- National Center for Atmospheric Research, Boulder, CO, USA
| | - Henry Selkirk
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
- Universities Space Research Association, Columbia, MD, USA
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9
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Measuring Methane Production from Ruminants. Trends Biotechnol 2015; 34:26-35. [PMID: 26603286 DOI: 10.1016/j.tibtech.2015.10.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/14/2015] [Accepted: 10/21/2015] [Indexed: 11/22/2022]
Abstract
Radiative forcing of methane (CH4) is significantly higher than carbon dioxide (CO2) and its enteric production by ruminant livestock is one of the major sources of greenhouse gas emissions. CH4 is also an important marker of farming productivity, because it is associated with the conversion of feed to product in livestock. Consequently, measurement of enteric CH4 is emerging as an important research topic. In this review, we briefly describe the conversion of carbohydrate to CH4 by the bacterial community within gut, and highlight some of the key host-microbiome interactions. We then provide a picture of current progress in techniques for measuring enteric CH4, the context in which these technologies are used, and the challenges faced. We also discuss solutions to existing problems and new approaches currently in development.
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10
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Hegglin MI, Plummer DA, Shepherd TG, Scinocca JF, Anderson J, Froidevaux L, Funke B, Hurst D, Rozanov A, Urban J, von Clarmann T, Walker KA, Wang HJ, Tegtmeier S, Weigel K. Vertical structure of stratospheric water vapour trends derived from merged satellite data. NATURE GEOSCIENCE 2014; 7:768-776. [PMID: 29263751 PMCID: PMC5734650 DOI: 10.1038/ngeo2236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/29/2014] [Indexed: 05/25/2023]
Abstract
Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere.
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Affiliation(s)
- M I Hegglin
- University of Reading, Department of Meteorology, Reading RG6 6BB, UK
| | - D A Plummer
- Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia V8W 3V6, Canada
| | - T G Shepherd
- University of Reading, Department of Meteorology, Reading RG6 6BB, UK
| | - J F Scinocca
- Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia V8W 3V6, Canada
| | - J Anderson
- Hampton University, Atmospheric and Planetary Science, Hampton, Virginia 23668, USA
| | - L Froidevaux
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91020, USA
| | - B Funke
- Instituto de Astrofisica de Andalucia, Granada 18008, Spain
| | - D Hurst
- NOAA Earth System Research Laboratory, Global Monitoring Divison, Boulder, Colorado 80305, USA
| | - A Rozanov
- University of Bremen, Institute of Environmental Physics, Bremen 28334, Germany
| | - J Urban
- Chalmers University of Technology, Department of Earth and Space Sciences, Gothenburg, 412 96, Sweden
| | - T von Clarmann
- Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - K A Walker
- University of Toronto, Toronto M5S 1A7, Canada
| | - H J Wang
- Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, Georgia 30332-0340, USA
| | | | - K Weigel
- University of Bremen, Institute of Environmental Physics, Bremen 28334, Germany
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11
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Rollins AW, Thornberry TD, Gao RS, Smith JB, Sayres DS, Sargent MR, Schiller C, Krämer M, Spelten N, Hurst DF, Jordan AF, Hall EG, Vömel H, Diskin GS, Podolske JR, Christensen LE, Rosenlof KH, Jensen EJ, Fahey DW. Evaluation of UT/LS hygrometer accuracy by intercomparison during the NASA MACPEX mission. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2014; 119:1915-1935. [PMID: 28845379 PMCID: PMC5571761 DOI: 10.1002/2013jd020817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Acquiring accurate measurements of water vapor at the low mixing ratios (< 10 ppm) encountered in the upper troposphere and lower stratosphere (UT/LS) has proven to be a significant analytical challenge evidenced by persistent disagreements between high-precision hygrometers. These disagreements have caused uncertainties in the description of the physical processes controlling dehydration of air in the tropical tropopause layer and entry of water into the stratosphere and have hindered validation of satellite water vapor retrievals. A 2011 airborne intercomparison of a large group of in situ hygrometers onboard the NASA WB-57F high-altitude research aircraft and balloons has provided an excellent opportunity to evaluate progress in the scientific community toward improved measurement agreement. In this work we intercompare the measurements from the Midlatitude Airborne Cirrus Properties Experiment (MACPEX) and discuss the quality of agreement. Differences between values reported by the instruments were reduced in comparison to some prior campaigns but were nonnegligible and on the order of 20% (0.8 ppm). Our analysis suggests that unrecognized errors in the quantification of instrumental background for some or all of the hygrometers are a likely cause. Until these errors are understood, differences at this level will continue to somewhat limit our understanding of cirrus microphysical processes and dehydration in the tropical tropopause layer.
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Affiliation(s)
- A. W. Rollins
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - T. D. Thornberry
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - R. S. Gao
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - J. B. Smith
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - D. S. Sayres
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - M. R. Sargent
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - C. Schiller
- IEK-7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - M. Krämer
- IEK-7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - N. Spelten
- IEK-7, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - D. F. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - A. F. Jordan
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - E. G. Hall
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - H. Vömel
- GRUAN/Deutscher Wetterdienst, Lindenberg, Germany
| | - G. S. Diskin
- NASA Langley Research Center, Hampton, Virginia, USA
| | - J. R. Podolske
- NASA Ames Research Center, Moffett Field, California, USA
| | - L. E. Christensen
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - K. H. Rosenlof
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - E. J. Jensen
- NASA Ames Research Center, Moffett Field, California, USA
| | - D. W. Fahey
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
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12
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Hurst DF, Lambert A, Read WG, Davis SM, Rosenlof KH, Hall EG, Jordan AF, Oltmans SJ. Validation of Aura Microwave Limb Sounder stratospheric water vapor measurements by the NOAA frost point hygrometer. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2014; 119:1612-1625. [PMID: 28845378 PMCID: PMC5571760 DOI: 10.1002/2013jd020757] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Differences between stratospheric water vapor measurements by NOAA frost point hygrometers (FPHs) and the Aura Microwave Limb Sounder (MLS) are evaluated for the period August 2004 through December 2012 at Boulder, Colorado, Hilo, Hawaii, and Lauder, New Zealand. Two groups of MLS profiles coincident with the FPH soundings at each site are identified using unique sets of spatiotemporal criteria. Before evaluating the differences between coincident FPH and MLS profiles, each FPH profile is convolved with the MLS averaging kernels for eight pressure levels from 100 to 26 hPa (~16 to 25 km) to reduce its vertical resolution to that of the MLS water vapor retrievals. The mean FPH - MLS differences at every pressure level (100 to 26 hPa) are well within the combined measurement uncertainties of the two instruments. However, the mean differences at 100 and 83 hPa are statistically significant and negative, ranging from -0.46 ± 0.22 ppmv (-10.3 ± 4.8%) to -0.10 ± 0.05 ppmv (-2.2 ± 1.2%). Mean differences at the six pressure levels from 68 to 26 hPa are on average 0.8% (0.04 ppmv), and only a few are statistically significant. The FPH - MLS differences at each site are examined for temporal trends using weighted linear regression analyses. The vast majority of trends determined here are not statistically significant, and most are smaller than the minimum trends detectable in this analysis. Except at 100 and 83 hPa, the average agreement between MLS retrievals and FPH measurements of stratospheric water vapor is better than 1%.
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Affiliation(s)
- Dale F Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Alyn Lambert
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - William G Read
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Sean M Davis
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Karen H Rosenlof
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Emrys G Hall
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Allen F Jordan
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - Samuel J Oltmans
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
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13
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Kunz A, Müller R, Homonnai V, Jánosi IM, Hurst D, Rap A, Forster PM, Rohrer F, Spelten N, Riese M. Extending water vapor trend observations over Boulder into the tropopause region: Trend uncertainties and resulting radiative forcing. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2013; 118:11269-11284. [PMID: 29263978 PMCID: PMC5734648 DOI: 10.1002/jgrd.50831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Thirty years of balloon-borne measurements over Boulder (40°N, 105°W) are used to investigate the water vapor trend in the tropopause region. This analysis extends previously published trends, usually focusing on altitudes greater than 16 km, to lower altitudes. Two new concepts are applied: (1) Trends are presented in a thermal tropopause (TP) relative coordinate system from -2 km below to 10 km above the TP, and (2) sonde profiles are selected according to TP height. Tropical (TP z > 14 km), extratropical (TP z < 12 km), and transitional air mass types (12 km < TP z < 14 km) reveal three different water vapor reservoirs. The analysis based on these concepts reduces the dynamically induced water vapor variability at the TP and principally favors refined water vapor trend studies in the upper troposphere and lower stratosphere. Nonetheless, this study shows how uncertain trends are at altitudes -2 to +4 km around the TP. This uncertainty in turn has an influence on the uncertainty and interpretation of water vapor radiative effects at the TP, which are locally estimated for the 30 year period to be of uncertain sign. The much discussed decrease in water vapor at the beginning of 2001 is not detectable between -2 and 2 km around the TP. On lower stratospheric isentropes, the water vapor change at the beginning of 2001 is more intense for extratropical than for tropical air mass types. This suggests a possible link with changing dynamics above the jet stream such as changes in the shallow branch of the Brewer-Dobson circulation.
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Affiliation(s)
- A. Kunz
- Institut für Energie– und Klimaforschung: Stratosphäre, Forschungszentrum Jülich, Jülich, Germany
| | - R. Müller
- Institut für Energie– und Klimaforschung: Stratosphäre, Forschungszentrum Jülich, Jülich, Germany
| | - V. Homonnai
- Department of Physics of Complex Systems, Eötvös Loránd University, Budapest, Hungary
| | - I. M. Jánosi
- Department of Physics of Complex Systems, Eötvös Loránd University, Budapest, Hungary
| | - D. Hurst
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
- Global Monitoring Division, NOAA Earth System Research Laboratory, Boulder, Colorado, USA
| | - A. Rap
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - P. M. Forster
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - F. Rohrer
- Institut für Energie– und Klimaforschung: Troposphäre, Forschungszentrum Jülich, Jülich, Germany
| | - N. Spelten
- Institut für Energie– und Klimaforschung: Stratosphäre, Forschungszentrum Jülich, Jülich, Germany
| | - M. Riese
- Institut für Energie– und Klimaforschung: Stratosphäre, Forschungszentrum Jülich, Jülich, Germany
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14
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Sargent MR, Sayres DS, Smith JB, Witinski M, Allen NT, Demusz JN, Rivero M, Tuozzolo C, Anderson JG. A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:074102. [PMID: 23902086 DOI: 10.1063/1.4815828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT∕LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT∕LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-α hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-α, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons, in which differences of 1.5-2 ppmv were routinely observed, and demonstrates that the accuracy of HHH is consistent with other instruments which use a range of detection methods and sampling techniques.
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Affiliation(s)
- M R Sargent
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
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15
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Numerical Modeling of Climate-Chemistry Connections: Recent Developments and Future Challenges. ATMOSPHERE 2013. [DOI: 10.3390/atmos4020132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Wang S, Li KF, Pongetti TJ, Sander SP, Yung YL, Liang MC, Livesey NJ, Santee ML, Harder JW, Snow M, Mills FP. Midlatitude atmospheric OH response to the most recent 11-y solar cycle. Proc Natl Acad Sci U S A 2013; 110:2023-8. [PMID: 23341617 PMCID: PMC3568342 DOI: 10.1073/pnas.1117790110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hydroxyl radical (OH) plays an important role in middle atmospheric photochemistry, particularly in ozone (O(3)) chemistry. Because it is mainly produced through photolysis and has a short chemical lifetime, OH is expected to show rapid responses to solar forcing [e.g., the 11-y solar cycle (SC)], resulting in variabilities in related middle atmospheric O(3) chemistry. Here, we present an effort to investigate such OH variability using long-term observations (from space and the surface) and model simulations. Ground-based measurements and data from the Microwave Limb Sounder on the National Aeronautics and Space Administration's Aura satellite suggest an ∼7-10% decrease in OH column abundance from solar maximum to solar minimum that is highly correlated with changes in total solar irradiance, solar Mg-II index, and Lyman-α index during SC 23. However, model simulations using a commonly accepted solar UV variability parameterization give much smaller OH variability (∼3%). Although this discrepancy could result partially from the limitations in our current understanding of middle atmospheric chemistry, recently published solar spectral irradiance data from the Solar Radiation and Climate Experiment suggest a solar UV variability that is much larger than previously believed. With a solar forcing derived from the Solar Radiation and Climate Experiment data, modeled OH variability (∼6-7%) agrees much better with observations. Model simulations reveal the detailed chemical mechanisms, suggesting that such OH variability and the corresponding catalytic chemistry may dominate the O(3) SC signal in the upper stratosphere. Continuing measurements through SC 24 are required to understand this OH variability and its impacts on O(3) further.
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Affiliation(s)
- Shuhui Wang
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
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17
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Shibata T, Hayashi M, Naganuma A, Hara N, Hara K, Hasebe F, Shimizu K, Komala N, Inai Y, Vömel H, Hamdi S, Iwasaki S, Fujiwara M, Shiotani M, Ogino SY, Nishi N. Cirrus cloud appearance in a volcanic aerosol layer around the tropical cold point tropopause over Biak, Indonesia, in January 2011. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd017029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Whiteman DN, Vermeesch KC, Oman LD, Weatherhead EC. The relative importance of random error and observation frequency in detecting trends in upper tropospheric water vapor. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016610] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Kevin C. Vermeesch
- NASA Goddard Space Flight Center, Code 612; Greenbelt Maryland USA
- Science Systems and Applications, Inc.; Lanham Maryland USA
| | - Luke D. Oman
- NASA Goddard Space Flight Center, Code 614; Greenbelt Maryland USA
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