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HMS: Hydrologic Micro Services

Workflow - Precip compare

This page contains detailed information for the precipitation comparison component.

On this page:

Description

This workflow automatically retrieves and compares precipitation time-series data from up to four national sources. NCIE station data are compared with data from a user selected subset of gridded data sources. The three gridded data sources available for selection are NLDAS, GLDAS, and TRMM. The workflow underneath uses HMS Precipitation Data Extraction workflow to retrieve and format precipitation data.

The workflow produces summary statistics for each of the data sources along with statistics comparing gridded sources with NCEI. The time series of data downloaded for the time period and location can be downloaded as a CSV or JSON.

Selecting an Area of Interest

Location can be specified as NHDPlus COMID or NCEI station ID. If NCEI station is selected as the location, then data from the user supplied Station ID are compared with user selected gridded data sources at the location of the NCEI station. The workflow provides the option of spatial aggregation of gridded precipitation data when NHDPlus COMID is selected as the location. Percentage of each grid cell covering the COMID catchment is calculated and used in averaging of the data for the catchment.

The workflow also lets the user specify an NCEI station ID when NHDPlus COMID is selected as the location. If the user opts not to specify an NCEI station ID, then the workflow finds and uses the NCEI station closest to the NHDPlus COMID catchment centroid. When NHDPlus COMID is selected it should be noted that the NCEI station used in comparison may not lie in the same time zone as the COMID catchment and that the workflow doesn’t account for the incompatibility of time zones.

Timezone of the Time-Series

The workflow converts time-series from GMT to local time-zone for NLDAS, GLDAS, and TRMM to compare with NCIE time-series which is in local time. A uniform distribution of values is assumed within a time step for gridded data sources when converting to local time zone. A temporal resolution of daily, monthly, annual or user specified extreme precipitation event can be chosen for comparison. Summary statistics are provided for each of the data sources along with statistics comparing gridded sources with NCEI. The time series of data downloaded for the time period and location can be downloaded as a CSV or JSON.

Capabilities

Version - 0.1

  1. Capability 1.
  2. Capability 2.
  3. Capability 3.
  4. Capability 4.
  5. Capability 5.

Input Parameters

Attributes of the HMS Precipitation Comparison input object
ParameterDataTypeDescriptionComments
NHDPlus COMIDStringNHDPlusV2.1 catchment COMID.Used only when 'catchment Centroid' is selected for 'Location Option'.
Weighted Spatial AverageCheckboxUse weighted spatial average data instead of point source data.Spatially aggregate gridded data to NHDPlus catchment COMID.
Use NCEI Station IDCheckboxUse NCEI station as point area of interest.Allows the use of a NCEI station ID as the specified area of interest.
Data SourcesCheckboxesGridded Data SourcesValid sources: nldas, gldas, and trmm
NCEI Station IDStringNOAA NCEI station identification number e.g. GHCND:USW00013874Used only when “ncei” is selected for “Source”. Station identifiers can be obtained from NOAA’s tool at https://www.ncdc.noaa.gov/cdo-web/datatools/findstation
Start YearStringStart year for the output time-series. e.g., 2010
Data Availability

nldas: hourly 1/1/1979 – Present (~4-day lag); North America @ 0.125 deg resolution.
gldas: 3-hourly 1/1/2000-Present (~1-month lag); Global @ 0.250 deg resolution.
ncei: depends upon selected station
trmm: daily 12/31/1997-11/30/2019; Global 50 deg South and 50 deg North latitudes @.250 deg resolution.
End YearStringEnd year for the output time-series. e.g., 2010
Temporal AggregationSelectionTemporal aggregation level of the output time-seriesValid options: Daily, Monthly, Annual, Extreme Precipitation Event. ‘5 Day total precip threshold’ means total precipitation for the previous five days and ‘Daily precip threshold’ means precipitation for the day being compared.

Output Parameters

Attributes of the HMS Precipitation Comparison output object
ColumnDataTypeDescription
datasetStringPrimary dataset of the requested timeseries. Some API calls return more than one dataset,either for a workflow API or other relevent dataset.
dataSourceStringPrimary source of the requested timeseries.
metaDataDictionaryMetadata for the output timeseries, includes metadata from the source as well as HMS metadata.
dataDictionaryOutput timeseries data is returned as a dictionary, where the key is the datetime stamp and value is a list of values for the source/dataset.

Web Service Details

Swagger UI


HTTP API

MethodURL
POSThttps://qed.epa.gov/hms/rest/api/v3/workflow/precip_compare/

Change Log

Version: 0.1 Beta : May 29, 2019

  1. Production UI and documentation initial setup.

Code Samples

Usage Title 1

Problem Statement: NA 1.

Desired Information: NA 1.

Information Returned from Service: NA 1.

Sample code for accessing API