MILAGRO (Megacity Initiative: Local and Global Research Observations)
March 30, 2006
MILAGRO (Megacity Initiative: Local and Global Research Observations), a multinational, multi-agency field experiment took place in Mexico during the month of March and is now drawing to a close. The purpose of the experiment was to study the air pollution generated by the Mexico City megacity and the pollution's transport and evolution. The experiment brought together U.S. and Mexican researchers and institutions. It involved 3 comprehensively equipped ground sampling stations with AERONET sun/sky radiometers in and near Mexico City, as well as several additional sites in various places around the country. There were a total of 6 aircraft plus several tethered balloons involved in the experiment. Most of the aircraft were based in Veracruz Mexico, and 3 of the aircraft were NASA sponsored. Full Story

Sun-Climate Center Seminar Series
March 27, 2006
The Sun-Climate Center seminar series kicked off last Monday, March 20. The first seminar, by Dr. Raimund Muscheler of UMBC-GEST and the Climate and Radiation Branch, was titled “Solar activity changes on centennial to millennial time scales inferred from radionuclide records.” Dr. Muscheler briefly discussed the physical mechanisms of the relationship between solar activity and variations of the isotopes in ice cores and tree rings. From analysis of isotopes in ice cores and tree rings, one may infer solar activity changes over a time scale thousands to millions of years. Full Story

Model Upgrades to Simulate the Influence of Anthropogenic Aerosols on Circulation and Rainfall
March 16, 2006
We have identified the Liu and Penner (2005) methodology to parameterize the homogeneous and heterogeneous ice-nucleation to compliment the current Nenes and Seinfield (2003) water cloud scheme that is already in the GCM. Together, the two schemes are expected to realistically address the question related to the effect of anthropogenic activities on nucleating clouds and influencing precipitation intensity and cloud radiative forcing of the Planet Earth. Full Story

Tibetan Plateau as an Atmospheric "Heat Pump"
March 8, 2006
In their recent paper entitled "Asian summer monsoon anomalies induced by aerosol direct forcing - the role of the Tibetan Plateau”, the authors, William Lau (NASA/GSFC), Maeng- Ki Kim (Kongju National University, Korea), and Kyu-Myong Kim (SSAI and the Climate and Radiation Branch), proposed “Elevated Heat Pump” as a plausible mechanism for the aerosol impact on the Asian summer monsoon involving interaction with physical processes over the Tibetan Plateau. According to the General Circulation Model experiment with seasonally varying aerosol forcing, the rising warm air heated by absorbing aerosol (dust and black carbon) over the Indo-Gangetic Plain and the southern slope of Tibet draws in warm and moist air from the Indian Ocean, leading to forced ascent, and enhanced convection over northern India in May-June, and subsequently to increased summer monsoon rainfall over continental India in June-July. This effect demonstrates the importance of the Tibetan Plateau in facilitating the impact of aerosols impacting the water cycle variability of the Asian monsoon. Full Story