Assessing land surface albedo bias in models of tropical climate
Abstract
socio-economic stability and military operations. Although research and operational forecasting in recent years have strongly focused on sea surface temperature as a cause of atmospheric variability, tropical circulations are also known to respond to changes in land surface boundary conditions. Land surface albedo is of particular importance because it controls the net flux of energy from land into the atmosphere, and is typically more persistent than land surface temperature or soil moisture. This proposed work will quantify bias in land surface albedo in an ensemble of climate models and in the Navy Global Environmental Model (NAVGEM), and relate this bias to errors in simulated tropical circulations. Multiple observational estimates of land surface albedo will be compared to model output from phase 5 of the Coupled Model Intercomparison Project (CMIP5) and to NAVGEM analyses and short-term and extended forecasts. This project will focus on two particular applications: the Somali jet and African easterly waves. The Somali jet constitutes a large part of the global cross-equatorial atmospheric mass flux during boreal summer, and is a good dynamical index of the South Asian monsoon; it is closely associated with the vertical wind shear that suppresses tropical cyclone formation in that summer monsoon domain. African easterly waves, which are precursors of many Atlantic tropical cyclones, are thought to originate from instability of the African easterly jet, which in turn is generated by surface heat fluxes over the Sahel and the Sahara Desert. Both the Somali jet and African easterly waves will thus be sensitive to the albedo of the proximal monsoon continent. This project will quantify simulated activity of the Somali jet and African easterly waves and relate this activity to model albedo bias. Simple modifications of NAVGEM surface albedo will be performed to estimate the degree to which correcting albedo bias can remediate circulation bias. This project is expected to improve the fidelity of numerical simulations of weather and climate, and to deepen understanding of the fundamental role played by the land surface in tropical climate. The project directly addresses the ONR Marine Meteorology program goal of improving atmospheric prediction in marine and coastal zones. Total funds requested for 2-year period: by Yale: $306,756 by Naval Research Laboratory - Monterey: $133,700
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2016
- Source ID
- N000141512531
Entities
People
- William R. Boos
Organizations
- Office of Naval Research
- United States Navy
- Yale University