H169-0006
Global Analysis of Atmospheric Rivers Precipitation using Remote Sensing and Reanalysis Products

Tuesday, 15 December 2020
Poster
Alireza Arabzadeh1, Mohammad Reza Ehsani2, Bin Guan3, Stella Heflin2 and Ali Behrangi2, (1)University of Arizona, Tucson, AZ, United States, (2)University of Arizona, Department of Hydrology and Atmospheric Sciences, Tucson, AZ, United States, (3)University of California, Los Angeles, Joint Institute for Regional Earth System Science and Engineering, Los Angeles, CA, United States
Abstract:
In the present study, and in light of the availability of global datasets, a global analysis of Atmospheric rivers (AR) precipitation is conducted using various precipitation products covering 18 years starting in 2001. More specifically we investigate, (1) the frequency of ARs occurrence, (2) precipitation intensity and volume of AR and Non-AR events, and (3) precipitation extremes and their relationship with AR events. Our analysis includes four widely used satellite precipitation (IMERG V6, GPCP Daily V1.3, bias-adjusted CMORPH V1, PERSIANN-CDR), and two well-known reanalysis products (MERRA-2 and ERA5).

Extreme precipitation events are investigated both globally at each grid cell and zonally averaged using remote sensing and reanalysis precipitation products. Besides, regions over land where ARs have a large impact (e.g. floods due to ARs’ precipitation) are specifically explored.

Our results show that over the oceans (especially the Southern Ocean), the contribution of ARs to the total precipitation and extreme events is larger than overland. However, some coastal areas over land (e.g., the Western/Eastern US) are highly affected by ARs. Maps of the fraction of AR precipitation to total precipitation and AR-related extremes specify higher values over coastal regions in the subtropics compared to other regions over land. West Coast receives 51-65% (based on four different products) of its annual precipitation from ARs and in west of the Erope this fraction reaches to 45-49%. The results show West/East Coast and East Asia experience about 70% of the extreme events in the presence of ARs in Dec-Feb and Mar-May.

There is a better agreement among products over the tropics than in higher latitudes. The largest inconsistencies among the products occur over the Southern Ocean and reanalysis products often deviate significantly from satellite-based products in remote regions over land (e.g., North Africa).

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