Mountain Mapper QPE - Warning Decision Training Division (WDTD)
Mountain Mapper QPE
Algorithm that improves upon quantitative precipitation estimates (QPE) in the Western U.S. where complex terrain affects radar estimates and gauge density. It uses the Parameter-Elevation Regressions on Independent Slopes Model (PRISM) to create continuous grid estimates of hourly precipitation climatologies to compare against gauge observations. As of Version 12, it is used as an input to the Multi-Sensor QPE product.
- 1-, 3-, 6-, 12-, 24-, 48-, and 72-hour accumulations
NWS: WFO, RFC
PRISM monthly precipitation climatology, HADS and MADIS gauge data
Spatial resolution: 1km x 1km
Temporal resolution: Updated hourly at the top of the hour. All products end at the indicated time.
As of Spring 2020, this product is available in two ways (but its creation is the same):
- The operational AWIPS system still supports the MRMS Version 11.5 suite of products; therefore, this product is available in the MRMS menu for viewing.
- As of MRMS Version 12, this product will not be supported as a standalone product, but rather, as an input to the Multi-Sensor QPE. Once Version 12 fully replaces V11.5 on the SBN, you will only be able to access this product via the MRMS Development site.
The Mountain Mapper product is based on a comparison of the Parameter-Elevation Regressions on Independent Slopes Model (PRISM) monthly precipitation climatologies (divided into hourly grids) and the real-time hourly gauge observations, via a ratio bias at each gauge site. PRISM is a tool that uses point measurements of precipitation and temperature, a digital elevation model (DEM), and expertise of complex climatic features to create continuous gridded estimates of monthly climatic parameters. The ratio biases are interpolated onto the MRMS grid, and then multiplied by the normalized PRISM hourly rainfall field to create the Mountain Mapper hourly analysis.
Latest update: MRMS Version 11.5 & 12
- Version 11.5 -- Operational AWIPS (via MRMS menu)
- Version 12 -- MRMS Development site (since it is only an input to the Multi-Sensor QPE product)
The following steps are only conducted on the one-hour accumulation estimate, since all the other accumulations are aggregates of the one-hour field:
- The PRISM monthly precipitation climatology (Figure 1) is evenly divided into hourly rainfall fields by dividing the monthly grid by the total number of hours in the month.
- A ratio (ek) is computed between the hourly gauge observation (gk) and the normalized PRISM hourly rainfall (pk) at each gauge site that has successfully passed the Gauge Quality Control.
- The ratio bias is then interpolated onto the MRMS grid using a similar inverse distance weighting (IDW) scheme as the Radar QPE w/ Gauge Bias Correction product.
- Unlike the Radar QPE w/ Gauge Bias Correction, the Mountain Mapper product uses predefined IDW parameters, b = 2 and D = 200 km.
- Finally, the interpolated ratio field is multiplied by the normalized PRISM hourly rainfall field to create the Mountain Mapper hourly analysis.
Zhang, J., K. Howard, S. Vasiloff, C. Langston, et al., 2011: National Mosaic and multi-sensor QPE (NMQ) system: description, results and future plans. Bull. Amer. Met. Soc., 92, 1321-1338.
Zhang, J., K. Howard, S. Vasiloff, C. Langston, B. Kaney, Y. Qi, L. Tang, H. Grams, D. Kitzmiller, J. Levit, 2014: Initial Operating Capabilities of Quantitative Precipitation Estimation in the Multi-Radar Multi-Sensor System. 28th Conf. on Hydrology, Amer. Meteor. Soc.
Daly, C., R. P. Neilson, and D. L. Phillips, 1994: A statistical-topographic model for mapping climatological precipitation for mountainous terrain. J. Appl. Meteor., 33, 140-158.