DOI: 10.5061/dryad.v9s4mw73g
title: Precipitation identifiers for meteorological features combining global GPM-IMERG retrievals and ERA5 reanalysis

description: The data collection provides 0.25-deg., 6-hourly global
 feature-precipitation categories from 2001 to 2019. The data is generated
 by merging GPM-IMERG observational rainfall (V6 final version) and
 atmospheric features identified by multiple object-based algorithms.
 Classified precipitation identifiers include rainfall associated with
 atmospheric rivers (AR), frontal systems (FT), low-pressure systems (LPS),
 mesoscale convective systems (MCS), and their co-occurrences (overlapping
 areas of features at a given time). In addition to algorithm-identified
 features, precipitation contributed from deep convection, non-deep
 convection, stratiform, and drizzle are pixel-wise defined using
 thresholds of CPC MERGE-IR brightness temperature and GPM-IMERG rain rate.
 The dataset is supported by the Department of Energy and Environment
 (DOEE): DE-SC0023244.
description: The categorization of global precipitation relies on recognizing
 four primary atmospheric features: atmospheric rivers (ARs), fronts (FTs),
 mesoscale convective systems (MCSs), and low-pressure systems (LPSs).
 Initially, identified atmospheric features with varying temporal and
 spatial resolutions are harmonized into a unified framework (6-hourly and
 0.25-degree). GPM-IMERG precipitation data (0.1-degree resolution) is then
 coarse-grained to 0.25-degree for labeling using merged feature outputs.
 Additionally, precipitation attributed to deep convection, non-deep
 convection, stratiform, and drizzle is discerned at the pixel level using
 MERGE-IR brightness temperature data alongside GPM-IMERG precipitation.
 These classifications exclusively apply to rainy pixels not aligned with
 the four primary features. Rainy pixels within a specific feature boundary
 are considered associated with that feature object. For frontal systems
 represented as line segments, the line-segment masks are expanded outward
 by 250 km to generate two-dimensional bounded features. The identification
 of precipitation sources is conducted independently every 6 hours over 19
 years (2001-2019). Detailed methodologies and demonstrations are
 accessible at https://docs.google.com/document/d/1O8NQesgyjIXv2X37wLsZ1EhgBdRKtvtPR7OYNBSBdBs/edit
description: # GPM-IMERG feature-associated precipitation identifiers 
 [https://doi.org/10.5061/dryad.v9s4mw73g](https://doi.org/10.5061/dryad.v9s4mw73g) A 19-year (2001-2019) global dataset of GPM-IMERG feature-associated precipitation identifiers. The precipitation identifier is generated to attribute a rainy grid to a specific meteorological feature. ## Description of the data and file structure ### Data description The data collection provides 0.25-deg., 6-hourly global feature-precipitation categories from 2001 to 2019. The data is generated by merging GPM-IMERG observational rainfall (V6 final version) and atmospheric features identified by multiple object-based algorithms. Classified precipitation identifiers include rainfall associated with atmospheric rivers (AR), frontal systems (FT), low-pressure systems (LPS), mesoscale convective systems (MCS), and their co-occurrences (overlapping areas of features at a given time). In addition to algorithm-identified features, precipitation contributed from deep convection, non-deep convection, stratiform, and drizzle are pixel-wise defined using thresholds of CPC MERGE-IR brightness temperature and GPM-IMERG rain rate. The dataset is supported by the Department of Energy and Environment (DOEE): DE-SC0023244. ### File information **File name:** "GPM-IMERG_feature_precip_{year}_{month}.nc" **File type:** NetCDF ([network Common Data Form](https://www.unidata.ucar.edu/software/netcdf/)) **Variable description:** precip_id [time, latitude, longitude]: An integer (1-20) corresponding to a classified precipitation identifier. The 20 classified precipitation identifers are described in the attribute of NetCDF and the supplementary document. ``` dimensions: time = 124 ; longitude = 1440 ; latitude = 481 ; variables: int64 time(time) ; time:units = "hours since 2001-01-01" ; time:calendar = "proleptic_gregorian" ; double longitude(longitude) ; longitude:_FillValue = NaN ; longitude:long_name = "longitude" ; longitude:short_name = "lon" ; longitude:units = "degrees_east" ; double latitude(latitude) ; latitude:_FillValue = NaN ; latitude:long_name = "latitude" ; latitude:short_name = "lat" ; latitude:units = "degrees_north" ; byte precip_id(time, latitude, longitude) ; ``` ## **Sharing / Access information** Data of identified atmospheric features is archived at [NERSC High Performance Storage System (HPSS)](https://docs.nersc.gov/systems/perlmutter/) (/global/cfs/cdirs/m4374/catalogues/raw_catalogue_files/observations/) Data of GPM-IMERG V6 Fianl version is archived at [NASA GES DISC](https://disc.gsfc.nasa.gov/) Data of CPC MERGE-IR is archived at [NOAA Climate Prediction Center](https://www.cpc.ncep.noaa.gov/products/global_precip/html/wpage.merged_IR.html) The data of GPM-IMERG feature-associated precipitation identifiers is derived from the above sources.