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Anthony Arendt edited this page Sep 28, 2016 · 2 revisions

Quantifying the Role of Dust on Precipitation, Snow, and Runoff in High Mountain Asia

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High Mountain Asia (HMA) is also known as the “Third Pole” due to it possessing the highest concentration of ice and snow outside of the Polar Regions. Under climate forcing, the timing and amount of snowfall over the region will be altered, which can change the regional water budget irrespective of changes in glacier and snowmelt runoff caused by warming temperatures. Complicating matters, snow and ice in the region is not pure; dust deposition in HMA can alter the surface albedo and influence cryosphere melt dynamics and feed back on broader circulation.

We propose the integration of dust satellite products (TOMS/OMI, MODIS and SeaWiFS) with global climate model simulations to quantify dust deposition events to explore year-to-year climate variability, the role of dust and surface albedo on the hydroclimate, and future hydroclimate of HMA. We will use a global atmospheric chemistry model, AM3 (at 50 km atmospheric resolution) and a high-resolution coupled global climate model, FLOR (also at 50 km atmospheric resolution). AM3 has previously been shown to be effective in reproducing dust transport in remote regions (Li et al. 2010). The atmospheric model resolution and physics in FLOR has previously been shown to be effective in representing the hydroclimate seasonal cycle of HMA (Kapnick et al. 2014). This 3-year project can be broken down into 3 main phases:

  1. We will develop a unique high-resolution database containing aerosol products from satellite data and AM3 simulations. With this database we propose to map for the first time the frequency and origin of aerosol events for the last 36 years over the entire HMA. Presently, aerosol loading and dust in particular are not available at resolutions below 1° on a mapped latitude/longitude grid; we will provide this information at high resolution (0.1°) on a mapped uniform grid for all products for ease of use for comparison and analysis without further post processing.

  2. Using the satellite record combined with atmospheric chemistry modeling to track aerosol deposition, we will implement a parameterization for the effect of aerosol deposition on the HMA cryosphere to explore feedbacks and sensitivities in the HMA hydroclimate. We will release GCM data at 50 km resolution over the region with and without aerosol deposition included for the historical record and also make available a long control simulation with constant forcing. Comparisons between these different simulations will allow us to rigorously quantify for the first time the role of aerosol deposition altering surface albedo and its affect on regional hydroclimate in the historical record.

  3. We will use the results of stages one and two to implement the observations-based model parameterization for the aerosol deposition influence on surface albedo to force a future projection simulation through 2100. When compared with projections without aerosol deposition, we can quantify the role of aerosols and surface albedo on future climate sensitivity and feedbacks. We expect that the regional hydroclimate sensitivity of the cryosphere will increase as a result of temperatures rising above freezing more often and changes in deposition leading to increased melt. This data set will be useful for others wishing to utilize GMELT to improve hazard mitigation planning and policy tools relating to regional changes in water resources over the next 1-100 years.

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