Workflow - Precip compare
This page contains detailed information for the precipitation comparison component.
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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.
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.
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.Input Parameters
Attributes of the HMS Precipitation Comparison input object
| Parameter | DataType | Description | Comments |
|---|---|---|---|
| NHDPlus COMID | String | NHDPlusV2.1 catchment COMID. | Used only when 'catchment Centroid' is selected for 'Location Option'. |
| Weighted Spatial Average | Checkbox | Use weighted spatial average data instead of point source data. | Spatially aggregate gridded data to NHDPlus catchment COMID. |
| Use NCEI Station ID | Checkbox | Use NCEI station as point area of interest. | Allows the use of a NCEI station ID as the specified area of interest. |
| Data Sources | Checkboxes | Gridded Data Sources | Valid sources: nldas, gldas, and trmm |
| NCEI Station ID | String | NOAA NCEI station identification number e.g. GHCND:USW00013874 | Used 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 Year | String | Start 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 Year | String | End year for the output time-series. e.g., 2010 | |
| Temporal Aggregation | Selection | Temporal aggregation level of the output time-series | Valid 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
| Column | DataType | Description |
|---|---|---|
| dataset | String | Primary dataset of the requested timeseries. Some API calls return more than one dataset,either for a workflow API or other relevent dataset. |
| dataSource | String | Primary source of the requested timeseries. |
| metaData | Dictionary | Metadata for the output timeseries, includes metadata from the source as well as HMS metadata. |
| data | Dictionary | Output 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
| Method | URL |
|---|---|
| POST | https://qed.epa.gov/hms/rest/api/v3/workflow/precip_compare/ |
Change Log
Version: 0.1 Beta : May 29, 2019
- Production UI and documentation initial setup.