Collaborative Research: Atmospheric Controls on Northern Hemisphere Cryosphere Variability

Project Details

Description

Abstract ATM-9314721 Robinson, David A. Rutgers University, New Brunswick Title: Atmospheric Controls on Northern Hemisphere Cryosphere Variability This award supports comprehensive study of relationships between atmospheric variability and fluctuations in the snow and sea ice covers the Northern Hemisphere. The primary thrust of the work is to provide a hemispheric synthesis of the sensitivity of the cryosphere to regional changes in the atmospheric circulation, and to diagnose this sensitivity with respect to associated interactions between precipitation, temperature, winds and the modes of large-scale teleconnection patterns. The PIs will identify those regions of the cryosphere warranting focused monitoring for potential climate change, and possible future responses of the cryosphere to changes in circulation regimes. As part of these efforts, they will perform a series of intercomparisons between observed snow cover patterns and those simulated by different GCMs under present and project future climatic conditions. The study will address at least six basic questions: 1) What are the relationships between variations in northern hemisphere sea ice extent and terrestrial snow cover? 2) What areas of the cryosphere exhibit strong or weak responses to atmospheric circulation changes and why? 3) Which areas contribute most strongly to northern hemisphere cryosphere variability? 4) What are the responses of the cryosphere to the modes of Large-scale teleconnections patterns, and how do these compare with parallel anomalies in synoptic activity, temperature and precipitation? 5) How well do different GCMs depict the present day distribution and variability of snow cover, and are changes in the cryosphere projected by GCMs in response to enhance CO2 warming reasonable from the viewpoint of modeled circulation changes? 6) Can the cryosphere be used as a robust indicator of climate change? For the snow and sea ice analyses, gridded NOAA charts of Northern Hemisphere snow extent and Navy/NOAA ice concentration data will be combined with available station records of snow depth, snow fall, precipitation and surface temperature. For atmospheric analyses, the PIs will use once to twice-daily NMC surface and upper-air fields from the early 1960s to present, used to calculate grid- point and regional time series of the frequency, position and strength of cyclones and anticyclones, storm tracks, and other indices of synoptic activity (e.g, positive vorticity advection), as well as temperature. Rawinsonde data from an existing archive will be used to analyze patterns of moisture flux convergence and their associations with snow cover and precipitation variations at high northern latitudes. Output from different GCMs will be obtained for doubled CO2 (equilibrium) runs, transient runs (in which CO2 is continually increased), as well as for runs using identical present-day boundary conditions. The research is a collaborative effort between University of Colorado (Drs. Mark Serreze and Roger G. Barry) and Rutgers University (Dr. David Robinson). The work is important because it seeks to clarify the role of the cryosphere in climate variability.

StatusFinished
Effective start/end date4/15/949/30/98

Funding

  • National Science Foundation: $121,366.00

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