Influence of climatic indices (AMO, PDO, and ENSO) and temperature on rainfall in the Northeast Region of India

Spatial diversity of atmospheric moisture transport and climate teleconnections over Indian subcontinent at different timescales

Regional weather and climate are generally impacted by global climatic phenomenon's. Understanding the impact of global climate phenomenon's on an atmospheric branch of the hydrological cycle is crucial to make advances in skillful precipitation forecast. The present study adopts a multiscale approach based on wavelets for unravelling the linkages between teleconnections and atmospheric moisture transport over homogeneous regions of Indian sub-continent. We investigated linkages between atmospheric moisture transport quantified as monthly integrated water vapor transport (IVT) during 1951-2022 over selected homogeneous regions and eight large scale climate oscillations using wavelet and global wavelet coherence. Our results indicate significant heterogeneity in linkages across different regions and across multiple timescales. In particular, the Indian Ocean Dipole (IOD) influence monthly IVT at intra-annual to inter-annual scale over all regions. The El Niño-Southern Oscillation (ENSO) have strong connection to monthly IVT at inter-annual scale whereas over west central region both IOD and ENSO strongly influence IVT at inter-decadal scale. While the Atlantic Multi-Decadal Oscillation and Pacific Decadal Oscillation have an impact on IVT in the north-east and southern regions, the Arctic Oscillation and North Atlantic oscillation have a strong inter-annual connection to IVT, majorly in the northwest and hilly regions. Overall, the methodology offers an effective approach for capturing the dynamics of atmospheric moisture transport in time-frequency space and provide a practical reference for prediction of atmospheric moisture transport linked precipitation over different regions of Indian subcontinent.

Regional Climate Change in Southeast Mexico-Yucatan Peninsula, Central America and the Caribbean

This study analyzes the mean, maximum, and minimum temperatures and precipitation trends in southeast Mexico-Yucatan Peninsula, Central America and the Caribbean regions. The Climate Research Unit (CRU) TS 4.01, with a spatial resolution of 0.5° × 0.5°, was the database used in this research. The trends of the four selected climate variables cover the period from 1960 to 2016. The results obtained show a clear and consistent warming trend, at a rate of about 0.01 °C/year for the entire study region. These results are consistent with some previous studies and the IPCC reports. While the trends of precipitation anomalies are slightly positive (~0.1 mm/year) for southeast Mexico-Yucatan Peninsula and almost the entire Caribbean, for Central America (CA) the trends are negative. The study also presents the correlation between temperatures and precipitation versus El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) drivers, indicating global warming and frequency signals from the climate drivers. In terms of the near future (2015–2039), three Representative Concentration Pathways (RPC) show the same trend of temperature increase as the historical record. The RCP 6.0 has trends similar to the historical records for CA and southeast Mexico-Yucatan Peninsula, while the Caribbean corresponds to RCP 4.5. In terms of the far-future (2075–2099), RCP 6.0 is more ad-hoc for southeastern Mexico-Yucatan Peninsula, and RCP 8.5 corresponds to Central America. These results could help to focus actions and measures against the impacts of climate change in the entire study region.