ИСТИНА

The spatial distribution and seasonal variability of anomalous moisture con-ditions associated with two types of El Niño and La Niña are investigated within the tropics. Five dryness indices (Keetch–Byram Drought Index, Weighted Anomaly Standardized Precipitation Index, Standardized Precipita-tion Index, Palmer Drought Severity Index, and Percent of Normal Precipita-tion) were derived from ECMWF (European Centre for Medium-Range Weather Forecasts) fifth generation reanalysis (ERA5) reanalysis and Uni-versity Corporation for Atmospheric Research (UCAR) datasets for the peri-od from 1979 to 2019. Cross-correlation and composite analysis were used to emphasize the response of dryness conditions to El Niño Southern Oscilla-tion (ENSO). Prior studies investigating the effects of ENSO on the surface moisture conditions mainly explored the response in precipitation, as well as in forest fires. However, there is still a limited understanding of how La Niña affects the surface moisture patterns and variability within many tropical re-gions. Another key uncertainty is how surface moisture conditions vary with two types of El Niño: (1) Eastern Pacific (EP) and Central Pacific (CP). Only a few studies have evaluated the impacts of so-called ENSO diversity on sur-face moisture conditions. These studies focused on how the two types of El Niño affect drought conditions in specific regions, such as the Amazon or Indonesia. Given the uncertainty in the interactions between ENSO phenom-ena and land surface moisture conditions, the main goal of our study was to investigate the spatial distribution and seasonal variation of the ENSO-induced anomalies of surface moisture conditions within humid and subhu-mid tropics, with a special focus on the different effects that are induced by two types of El Niño and La Niña. The results show a significant heterogene-ity of the ENSO-induced moisture anomaly conditions both within and across various geographical regions. Four main areas in tropics with the max-imum effects of El Niño/La Niña events on the surface moisture conditions were found: Southeast Asia and Australia, Eastern and South Africa, North-eastern and Eastern South America, and Central America. It was demonstrat-ed that the effect of La Niña is usually opposite to those of El Niño. The re-sponses to the two types of El Niño differed mostly in the moisture anomaly intensity and its spatial structure. The work was supported by Russian Scientific Foundation, grant No. 22-17-00073.