DOI: 10.5281/zenodo.4451901
title: Atmospheric River Database for the Himalayas

description: Atmospheric Rivers (ARs) are long and narrow regions of intense moisture transport in the lower troposphere. The dataset comprises of Atmospheric Rivers that have happened over the Himalayan Basins from 1982 to 2018. It includes the dates and times, duration, intensity/magnitude, tracks, and categories of the ARs. <strong>File Names and description:</strong> <strong>1. </strong><strong>ERA5_Persistant_Database2000km:</strong> This file includes the date, times, average Integrated Water Vapor Transport (IVT) magnitude (kg.m^-1s^-1), starting IVT, maximum IVT, and duration of ARs. These terms are explained below in greater details. <strong>Column “Date”:</strong> Gives the date and time (in Coordinated Universal Time UTC) of each AR timestep. The IVT data used to identify ARs is 6-hourly (00UTC, 06UTC, 12UTC and 18UTC). <strong>Column “AR_ID”:</strong> Each identified persistent AR, lasting for at least 18 hours, is given a unique ID, which remains same for all timesteps of the AR. This column gives the ID of ARs. The ID of an AR is based on the year in which the AR occurred, the letters “AR”, and the occurrence serial of the AR in the year. For example, the first AR in 1990 has ID 1980AR1. If the AR lasted for 10 timesteps, all 10 timesteps will have the same ID. <strong>Column “Ind”:</strong> This column gives the python index of IVT data in 6-hour yearly data, giving the date and time of each AR timestep. This column can be ignored since the same information is more directly available in “Date” column. <strong>Column “AvgIVT”:</strong> This column gives the average IVT magnitude (kg.m^-1s^-1) along the AR major axis, i.e., the gridcells that have maximum IVT along the AR track. For example, the first value corresponds to the average of all values from column <em>“0”</em> to column <em>“88”,</em> which give the IVT magnitude at each gridcell of the major axis of the first timestep. <strong>Column “StartIVT”:</strong> This column gives the IVT magnitude (kg.m^-1s^-1) at the initial gridcell on the first timestep when AR condition was identified. <strong>Column “ARDuration”:</strong> This column gives duration of the AR in hours; for example, an AR lasting for three timesteps will have the duration of 18 hours, an AR lasting for four timesteps will have duration of 24 hours. <strong>Column “MaxIVT”:</strong> This column gives the maximum of all IVT values (kg.m^-1s^-1) at the starting gridcells on each timestep of an AR. <strong>Column “ARCat”:</strong> This column gives category of the AR, based on IVT magnitude and duration of the ARs. Six categories have been defined, Cat0 denoting the weakest AR and Cat5 denoting the strongest AR. More details on this can be found in the accompanying paper. <strong>Column “0” to the end.</strong> These columns give the IVT magnitude (kg.m^-1s^-1) at each gridcell of the major axis of each AR timestep. <em>Note that the cyclone dates were not available before 1982, so AR dates for 1979 to 1981 includes cyclonic IVT structures.</em> <strong>2. </strong><strong>ERA5_Persistant_Database_lats_2000km:</strong> The file gives the latitudes of grid points of maximum IVT, i.e., the latitude of major axes of ARs throughout their duration. <strong><em>Columns “Date”, “AR_ID”, “Ind”, “AvgIVT”, “StartIVT”, “ARDuration”, “MaxIVT”, “ARCat” are the same as given above for “ERA5_Persistant_Database2000km.csv” file.</em></strong> <strong>Column “0” to end.</strong> These columns give the latitude ( in degrees North) at each gridcell of the major axis of each AR timestep. <strong>3. </strong><strong>ERA5_Persistant_Database_lons_2000km:</strong> The file gives the longitudes of grid points of maximum IVT, i.e., the longitudes of major axes of ARs throughout their duration Columns “Date”, “AR_ID”, “Ind”, “AvgIVT”, “StartIVT”, “ARDuration”, “MaxIVT”, “ARCat” are the same as given above for “ERA5_Persistant_Database2000km.csv” file. <strong>Column “0” to end.</strong> These columns give the longitude (in degrees East) at each gridcell of the major axis of each AR timestep
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