Global Intercomparison of Atmospheric Rivers Precipitation in Remote Sensing and Reanalysis Products

Abstract

Atmospheric rivers (ARs) play an important role in the total annual precipitation regionally and globally, delivering precious freshwater to many arid/semiarid regions. On the other hand, they may cause intense precipitation and floods with huge socioeconomic effects worldwide. In this study, we investigate AR-related precipitation using 18 years (2001-2018) of globally gridded AR locations derived from Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2). AR precipitation features are explored regionally and seasonally using remote sensing (Integrated Multi-satellitE Retrievals for GPM version 6 [IMERG V6], daily Global Precipitation Climatology Project version 1.3 [GPCP V1.3], bias-adjusted CPC Morphing Technique version 1 [CMORPH V1], and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks [PERSIANN-CDR]) and reanalysis (MERRA-2 and ECMWF Reanalysis 5th Generation [ERA5]) precipitation products. The results show that most of the world (except the tropics) experience more intense precipitation from AR-related events compared to non-AR events. Over the oceans (especially the Southern Ocean), the contribution of ARs to the total precipitation and extreme events is larger than over land. However, some coastal areas over land are highly affected by ARs (e.g., the western and eastern United States and Canada, Western Europe, North Africa, and part of the Middle East, East Asia, and eastern South America and part of Australia). Although spatial correlations for pairs of IMERG/CMORPH and GPCP/PERSIANN-CDR are fairly high, considerable discrepancies are shown in their estimation of AR-related events (i.e., overall IMERG and CMORPH show a higher fraction of AR-related precipitation). It was found that the degree of consistency between reanalysis and satellite-based products is highly regionally dependent, partly due to the uneven distribution of in situ measurements.

Investigating Various Products of IMERG for Precipitation Retrieval over Surfaces with and without Snow and Ice Cover

“…The observed underestimation over the mountainous west can be due to poor skill of satellite products in capturing orographic enhancement [25,42] and the fact that most of the annual precipitation over this region occurs in wintertime [43] and a large fraction of the that is through the atmospheric rivers [44,45]. However, it is important to note that radar beam blockage may also contribute to the lower quality of stage IV product in mountainous regions.…”

Investigating Various Products of IMERG for Precipitation Retrieval Over Surfaces With and Without Snow and Ice Cover

“…The observed underestimation over the mountainous west can be due to poor skill of satellite products in capturing orographic enhancement [16,33] and the fact that most of the annual precipitation over this region occurs in wintertime [34] and a large fraction of the that is through the atmospheric rivers [35,36]. However, it is important to note that radar beam blockage may also contribute to the lower quality of Stage IV product in mountainous regions.…”

Assessment of Snowfall Accumulation from Satellite and Reanalysis Products Using SNOTEL Observations in Alaska

“…Accurate estimations of rainfall, snowfall, and snowpack amount and distribution are thus important. While snowmelt remains a critical source of freshwater for the world population [1,2], in a warming climate, snowpack amounts are being reduced [3,4] and most precipitation may fall as rain instead of snow. However, snowfall is still the dominant form of precipitation in high latitudes [5][6][7].…”