ISPD version 4 subsetting

Regional and temporal subsetting is now available in RDA dataset ds132.2 for the International Surface Pressure Databank version 4 (ISPDv4).  This service is recommended for users who are interested in a local region and time period of interest without resorting to downloading a large volume of data files from the ISPDv4 archive.

To request a subset, go to the ds132.2 Data Access tab, then select "Get a subset".  Enter your time period and region of interest, then follow the instructions to submit your data request.  After submitting your request, the request will be processed on the NCAR computing system and we will send you an email notification with a download link when your data are ready.

Users can also browse an interactive map displaying ISPDv4 observation locations by using the Interactive Station Viewer tool.  Filters can be applied to display observation locations by time period, location, and observation type.

ERA5 Modes of Interannual Variability

ds633.3: ERA5 Modes of Interannual Variability

represents a suite of climate diagnostics for 56 variables relating to the interannual variability of ECMWF ERA5 monthly mean data. Basic fields for each variable include a monthly mean climatology and standard deviation, corresponding anomalies spanning 40 or more years of data, empirical orthogonal functions (EOFs), principal component (PC) time series, percent variance explained by each EOF, and an estimate of the standard error of the percent variance explained. Dominant modes of variability include El Nino Southern Oscillation (ENSO) in sea surface temperature, and the Antarctic Oscillation (AO) and North Atlantic Oscillation (NAO) in surface pressure. Separate analyses are performed for the entire globe, northern hemisphere only, and southern hemisphere only. There is sufficient information to further explore lagged correlations, teleconnections, and more advanced statistical techniques. Preparation and calculation of this dataset is performed by CISL DECS at NCAR. Code used for computing EOFs of scalar fields can be found at

https://github.com/NCAR/rda-ecmwf-processing/blob/master/ds633.3-ERA5/SUBR_eof_scalar.f90

RDA External Application API Update

The RDA has introduced an update to the RDA External Applications API. The REST API will now return JSON encoded responses to queries, which should improve interactivity and allow for more robust error handling.

In addition to the updated HTTPS responses, an updated version of the rdams-client.py script has been released. This new python client can be used as a command line tool (as in the past) or as an imported python module to interact with the response objects directly.

A Jupyter Notebook that outlines how to use the module programmatically can be found here:

https://github.com/NCAR/rda-apps-clients/blob/master/src/python/rdams_client_example.ipynb


The complete API documentation can be found here: REST API and JSON Responses documentation


To demonstrate just one use case,
If you were to do an HTTPS GET call of the following url:

GET https://rda.ucar.edu/json_apps/paramsummary/ds083.2

An Example Response

This response could then be programmatically parsed to find only variables that had a certain unit, or those that were in GRIB2 format.

{
   "status": "ok",
   "request_duration": "0.173482 seconds",
   "code": 200,
   "messages": [],
   "result": {
      "dsid": "083.2",
      "subsetting_available": true,
      "data": [
         {
            "native_format": "WMO_GRIB2",
            "param": "VIS",
            "GCMD_uuid": "9337898d-68dc-43d7-93a9-6afdb4ab1784",
            "units": "m",
            "param_description": "Visibility"
         },
         {
            "param_description": "Categorical snow (yes=1; no=0)",
            "native_format": "WMO_GRIB2",
            "param": "CSNOW"
         },
         {
            "native_format": "WMO_GRIB2",
            "param": "PEVPR",
            "standard_name": "potential_water_evaporation_flux",
            "GCMD_uuid": "b68ab978-6db6-49ee-84e2-5f37b461a998",
            "units": "W m^-2",
            "param_description": "Potential evaporation rate"
         },
         {
            "native_format": "WMO_GRIB2",
            "param": "T CDC",
            "GCMD_uuid": "acb52274-6c0d-4241-a979-3fa3efca6702",
            "units": "%",
            "param_description": "Total cloud cover"
         },

         ...

         {
            "native_format": "WMO_GRIB1",
            "param": "ABSV",
            "standard_name": "atmosphere_absolute_vorticity",
            "ISO_TopicCategoryCode": "climatologyMeteorologyAtmosphere",
            "units": "s^-1",
            "GCMD_uuid": "858a80ff-5aa4-4590-b2e2-e88a802a6ee4",
            "param_description": "Absolute vorticity"
         },
         {
            "native_format": "WMO_GRIB1",
            "param": "VVEL",
            "standard_name": "lagrangian_tendency_of_air_pressure",
            "ISO_TopicCategoryCode": "climatologyMeteorologyAtmosphere",
            "units": "Pa s^-1",
            "GCMD_uuid": "841a7ac7-5981-4e93-895f-1b57c3d892a0",
            "param_description": "Vertical velocity (pressure)"
         }
      ]
   },
   "request_end": "2020-03-03T10:52:38.637789",
   "request_start": "2020-03-03T10:52:38.464307"
}