The GPM Ground Validation Airborne Precipitation Radar 3rd Generation (APR-3) OLYMPEX V2 dataset was collected from November 12, 2015 to December 19, 2015 during the GPM Ground Validation Olympic Mountains Experiment (OLYMPEX) field campaign held in the Pacific Northwest. This dataset is version -2 (V2) of the APR-3, an enhanced and upgraded instrument derived from the APR-2 used in previous field campaigns. APR-3 has the addition of W-band measurement capability, and scans cross-track from +/- 25° to the right and left of nadir. Ku-band, Ka-band, and W-band frequency Doppler measurements are made by APR-3 from the DC-8 aircraft at 10 km altitude during OLYMPEX. The APR-3 dataset files are in HDF-5 format with JPG format browse images. This dataset contains radar reflectivity, Doppler velocity for all bands, linear depolarization ratio at Ku-band, and normalized radar cross section measurements at Ka and Ku-bands.

The GPM Ground Validation Daily Precipitation Olympic Mountain Experiment (OLYMPEX) dataset consists of a single netCDF-4 data file containing estimates of daily precipitation, both rainfall and snowfall amounts, on a 1/32 degree spatial resolution grid covering the extent of the OLYMPEX field campaign region in the Olympic Mountains of the state of Washington. This data product was created for the GPM Ground Validation OLYMPEX field campaign. These VIC precipitation estimates are based on NOAA WSR-88D radar and rain gauge data incorporated in NOAA’s National Severe Storms Laboratory (NSSL) local gauge bias-corrected radar quantitative precipitation estimation (QPE) model (product Q3GC) and the Mountain Mapper QPE model (product Q3MM). The VIC hydrology model was used to invert the snow water equivalent (SWE) values to derive precipitation through adjustment of the precipitation-weighting factor on a grid cell by grid cell basis. The VIC precipitation data are available from October 1, 2015 through April 30, 2016.

The GPM Ground Validation KATX NEXRAD OLYMPEX dataset contains data from selected NEXt Generation Weather RADar system (NEXRAD) instruments in operation during the Olympic Mountains Experiment (OLYMPEX) field campaign to help support the ground validation of the Global Precipitation Measurement (GPM). NEXRAD is a network of 160 stationary S-Band radars dispersed throughout the United States and select locations abroad. Datasets gathered from three NEXRAD stations, as listed below, extend from 22 September 2015 through 01 May 2016 as part of the GPM Ground Validation OLYMPEX data. This dataset contain browse images of base reflectivity observations in the Portable Network Graphic (PNG) format. Base radar reflectivity is the measure of transmitted power returned to the radar after intercepting a target, for example, rain droplets. This information can illustrate the amount and size distribution of water particles in a given unit volume of atmosphere.

The GPM Ground Validation Environment Canada (EC) Manual Precipitation Measurements GCPEx dataset was collected during the GPM Cold-season Precipitation Experiment (GCPEx) in Ontario, Canada with data collections from January 18 - March 28, 2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. Precipitation amount, weight, snow water equivalent and present weather condition were recorded using a Tretyakov gauge inside a double fence intercomparison reference (DFIR) shield.

The GPM Ground Validation Snow Depth Monitoring System OLYMPEX dataset consists of snow depth, temperature, and relative humidity measurements which were collected using snow depth poles, time lapse cameras, temperature/relative humidity sensors, and manual snow surveys. This dataset was collected during the GPM Ground Validation Olympic Mountain Experiment (OLYMPEX) held on the Olympic Peninsula in the Pacific Northwest of the United States. The analyzed data files are available in netCDF-3 data format. The dataset includes the individual camera photos of snow poles taken hourly during the field campaign, provided as JPG images. There are up to 3 cameras/poles per study site location. In addition, a Microsoft Excel data file contains results of a manual snow survey taken on the specific days of the Airborne Snow Observatory OLYMPEX overflights. In total, measurements contained in this dataset extend from September 5, 2014 through August 20, 2016, but the primary field campaign data were collected during the fall 2015 to spring 2016 time period.

The GPM Ground Validation Environment Canada (EC) Micro Rain Radar (MRR) GCPEx V2 dataset was collected from the Micro Rain Radar (MRR) during the GPM Cold-season Precipitation Experiment (GCPEx) in Ontario, Canada during the winter season 2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. Operating at 24 GHz the MRR, a vertically pointing Doppler radar, retrieved quantitative rain rates, drop size distributions, radar reflectivity, and fall velocities on vertical profiles up to several kilometers above the unit. The MRR used during GCPEX is the second generation of the instrument manufactured by METEK (URL: http://metek.de/product/mrr-2/). Version 2 of this dataset became active on April 30, 2015.

The GPM Ground Validation KLGX NEXRAD OLYMPEX dataset contains data from selected NEXt Generation Weather RADar system (NEXRAD) instruments in operation during the Olympic Mountains Experiment (OLYMPEX) field campaign to help support the ground validation of the Global Precipitation Measurement (GPM). NEXRAD is a network of 160 stationary S-Band radars dispersed throughout the United States and select locations abroad. Datasets gathered from three NEXRAD stations, as listed below, extend from 22 September 2015 through 01 May 2016 as part of the GPM Ground Validation OLYMPEX data. This dataset contain browse images of base reflectivity observations in the Portable Network Graphic (PNG) format. Base radar reflectivity is the measure of transmitted power returned to the radar after intercepting a target, for example, rain droplets. This information can illustrate the amount and size distribution of water particles in a given unit volume of atmosphere.

The GPM Ground Validation Micro Rain Radar (MRR) OLYMPEX dataset was gathered during the Global Precipitation Measurement (GPM) Ground Validation OLYMPEX field campaign held at Washington’s Olympic Peninsula from October 31, 2014 through May 22, 2016. The dataset contains measured and derived data from MRR instruments placed in four separate locations within the study region. The MRR is a Biral/Metek 24 GHz (K-band) vertically oriented Frequency Modulated Continuous Wave (FM-CW) radar that measures signal backscatter from which Doppler spectra, radar reflectivity, Doppler velocity, drop size distribution, rain rate, liquid water content, and path integrated attenuation are derived. Data files are available in ASCII data format.

The GPM Ground Validation Environment Canada (EC) Precipitation Occurrence Sensor System (POSS) GCPEx dataset is comprised of data gathered during the GPM Cold-season Precipitation Experiment (GCPEx), which took place in Ontario, Canada, January 15 - March 1, 2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. The POSS is a bi-static X-band Doppler radar designed by Environment Canada. The POSS measures a signal whose frequency is proportional to the particle Doppler velocity and whose amplitude is proportional to the particle scattering cross-section. Its measurements can be used to provide information regarding precipitation occurrence, type, rate, and raindrop size distribution.