BER launches Environmental System Science Program. Visit our new website under construction!

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

BER Research Highlights


Regime Dependence of Cloud Water Variability
Published: May 10, 2016
Posted: July 29, 2016

Using ARM data from multiple observational sites around the globe, scientists gain insights into cloud variability.

The Science
Physical processes, such as the interaction of clouds with sunlight or the rate at which clouds produce rain, depend on the amount of cloud water available locally at scales smaller than can be represented by current global model grid resolutions.

The Impact
Using observations from U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program sites across the world, scientists have improved understanding of how the amount of water in clouds varies at small scales. Based on these observations, a new way of describing how cloud water varies with cloud regime has been developed for use in global weather and climate models. The new parameterization will enable models to calculate more accurate process rates by providing a better representation of how the amount of cloud water varies within the cloud at these subgrid scales.

Summary
A number of different retrieval products for cloud condensate from ARM observations are assessed for five different geographical regions for multiple years and seasons. The retrieval reliability varies with cloud type, but for cloud categories largely unaffected by precipitation, a comparison across sites and longer time periods is possible. These observations confirm previously documented variability behavior as a function of cloud fraction, but also reveal a systematic regime dependence that is not captured by existing parameterizations. Condensate variability measured as a fractional standard deviation (FSD) in warm boundary-layer clouds is greater in the tropics than in the mid- and high-latitudes for scenes with comparable cloud type and fraction, with the observed FSD varying from 1.2 in the tropics to 0.4 in the Arctic. A parameterization of the cloud liquid condensate FSD based on the grid box mean total water amount and cloud fraction is formulated and shown to better capture the observed range of FSD values across the different geographical sites and seasons.

Contacts (BER PM)
Shaima Nasiri
ASR Program Manager
Shaima.Nasiri@science.doe.gov
Sally McFarlane
ARM Program Manager
Sally.McFarlane@science.doe.gov

 (PI Contact)
Maike Ahlgrimm
European Centre for Medium-Range Weather Forecasts
maike.ahlgrimm@ecmwf.int

Funding
This work was supported by the U.S. Department of Energy's Office of Science, Office of Biological and Environmental Research through the Atmospheric System Research (ASR) activity. Grant Number: DE-SC0005259. Data was obtained from the Atmospheric Radiation Measurement (ARM) Climate Research Facility.

Publication
Ahlgrimm, M., and R. M. Forbes. 2016. “Regime Dependence of Cloud Condensate Variability Observed at the Atmospheric Radiation Measurement Sites,” Quarterly Journal of the Royal Meteorological Society 142(697), 1605-17. DOI: 10.1002/qj.2783. (Reference link)

Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling
  • Research Area: Atmospheric System Research
  • Facility: DOE ARM User Facility

Division: SC-33.1 Earth 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

Jan 11, 2022
No Honor Among Copper Thieves
Findings provide a novel means to manipulate methanotrophs for a variety of environmental and in [more...]

Dec 06, 2021
New Genome Editing Tools Can Edit Within Microbial Communities
Two new technologies allow scientists to edit specific species and genes within complex laborato [more...]

Oct 27, 2021
Fungal Recyclers: Fungi Reuse Fire-Altered Organic Matter
Degrading pyrogenic (fire-affected) organic matter is an important ecosystem function of fungi i [more...]

Oct 19, 2021
Microbes Offer a Glimpse into the Future of Climate Change
Scientists identify key features in microbes that predict how warming affects carbon dioxide emi [more...]

Aug 25, 2021
Assessing the Production Cost and Carbon Footprint of a Promising Aviation Biofuel
Biomass-derived DMCO has the potential to serve as a low-carbon, high-performance jet fuel blend [more...]

List all highlights (possible long download time)