Skip to main content
U.S. flag

An official website of the United States government

Dot Gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Assimilating Differential Reflectivity Columns Into The HIGH-RESOLUTION Rapid Refresh Using Latent Heating Forcing


The High Resolution Rapid Refresh (HRRR) assimilates radar reflectivity information in order to skillfully forecast convection. This assimilation is done using an empirical relationship between reflectivity and latent heat release from hydrometeor condensation and freezing to update the temperature tendency field. The temperature tendency field then forces the HRRR to produce updrafts where the temperature tendency is large and positive. Two problems with this approach are that areas of high reflectivity are temporally and spatially offset from vertical velocity maxima. Differential reflectivity (ZDR), which is now experimentally available on a national mosaic from the Multi Radar Multi Sensor (MRMS) project, provides a possible solution to these two problems. Vertical columns of enhanced ZDR above the environmental freezing level can be used as proxies for updrafts, so creating a two-dimensional field of ZDR column locations can focus the latent heating forcing to where convective updrafts are actively occurring. This presentation will discuss the algorithm used to detect ZDR columns and subjectively assess how well the analyzed ZDR columns match the expected locations of updrafts in convective events. The method used to create a temperature tendency field from ZDR column locations that can be assimilated into the HRRR will also be discussed. These ZDR column-derived temperature tendency fields will then be compared to the temperature tendency fields currently used by the HRRR that are derived from radar reflectivity in order to demonstrate the feasibility of assimilating ZDR columns instead of or in addition to radar reflectivity. Preliminary results from a case study in which ZDR column information is assimilated may also be presented.

Article / Publication Data
Available Metadata
Fiscal Year
Published On
January 01, 2018

This publication was presented at the following:

AMS 98th Annual meeting - 2018
American Meteorological Society
Conference presentation


Authors who have authored or contributed to this publication.