U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Sensitivity to Rimed Ice Species
Published: May 24, 2013
Posted: July 18, 2013

Despite a number of studies dedicated to the sensitivity of deep convection simulations to the properties of rimed (covered with ice) ice species in microphysics schemes, no consensus has been achieved on the nature of the impact. Considering the need for improved quantitative precipitation representation and forecasts, it is crucial that the cloud modeling community better understands the reasons for the differing conclusions among previous studies and knows the relevance of these sensitivities for the numerical weather prediction. Research conducted at Brookhaven National Laboratory examined the role of environmental conditions and storm type on the sensitivity of precipitation simulations to the nature of the rimed ice species (soft [graupel] or hard hail). Idealized three-dimensional simulations of supercells and squall lines were performed in varying thermodynamic environments. These studies showed that, for simulation periods of sufficient length (> 2h), graupel-containing and hail-containing storms produce domain-averaged surface precipitation more similar than many earlier studies suggest. While graupel is lofted to higher altitudes and has a longer residence time aloft than hail, the simulations suggest that most of this graupel eventually reaches the surface and the surface precipitation rates of hail- and graupel-containing storms converge. However, environmental conditions play an important role in the magnitude of this sensitivity. Storms in large-CAPE environments (typical of storms in the midwestern United States) are more sensitive than their low-CAPE counterparts (typical of storms in Europe) to the nature of rimed ice species in terms of domain-average surface precipitation. Supercells are more sensitive than squall lines to the nature of the rimed ice species in terms of spatial precipitation distribution and peak precipitation (disregarding of the amount of CAPE).

Reference: K. Van Weverberg. 2013. “Impact of Environmental Instability on Convective Precipitation Uncertainty Associated with the Nature of the Rimed Ice Species in a Bulk Microphysics Scheme,” Monthly Weather Review, DOI: http://dx.doi.org/10.1175/MWR-D-13-00036.1. (Reference link)

Contact: Dorothy Koch, SC-23.1, (301) 903-0105
Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling
  • Research Area: Atmospheric System Research

Division: SC-23.1 Climate and Environmental Sciences Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)