The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with ...The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO4^2-, hydrophobic and hydrophilic black carbon （BC） and organic carbon compounds （OC）, including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion （especially in the aqueous phase） and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO4^2- shows less horizontal gradient and seasonality than SO2, with wet deposition （60%） and export （27%） being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition （60%） and export （30%）. The simulated spatial and seasonal SO4^2-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.展开更多
An ideal and simple formulation is successfully derived that well represents a quasi-linear relationship found between the domain-averaged water vapor, Q （ram）, and temperature, T （K）, fields for the three tropica...An ideal and simple formulation is successfully derived that well represents a quasi-linear relationship found between the domain-averaged water vapor, Q （ram）, and temperature, T （K）, fields for the three tropical oceans （i.e., the Pacific, Atlantic and Indian Oceans） based on eleven GEOS-3 [Goddard Earth Observing System （EOS） Version-3] global re-analysis monthly products. A Q - T distribution analysis is also performed for the tropical and extra-tropical regions based on in-situ sounding data and numerical simulations [GEOS-3 and the Goddard Cumulus Ensemble （GCE） model]. A similar positively correlated Q - T distribution is found over the entire oceanic and tropical regions; however, Q increases faster with T for the former region. It is suspected that the tropical oceans may possess a moister boundary layer than the Tropics. The oceanic regime falls within the lower bound of the tropical regime embedded in a global, curvilinear Q - T relationship. A positive correlation is also found between T and sea surface temperature （SST）; however, for one degree of increase in T, SST is found to increase 1.1 degrees for a warmer ocean, which is slightly less than an increase of 1.25 degrees for a colder ocean. This seemingly indicates that more （less） heat is needed for an open ocean to maintain an air mass above it with a same degree of temperature rise during a colder （warmer） season [or in a colder （warmer） region]. Q and SST are also found to be positively correlated. Relative humidity （RH） exhibits similar behaviors for oceanic and tropical regions. RH increases with increasing SST and T over oceans, while it increases with increasing T in the Tropics. RH, however, decreases with increasing temperature in the extratropics. It is suspected that the tropical and oceanic regions may possess a moister local boundary layer than the extratropics so that a faster moisture increase than a saturated moisture increase is favored for the former regions. T, Q, saturated water vapor, RH, and SST are also examined with regard to the warm and cold ＂seasons＂ over individual oceans. The Indian Ocean warm season dominates in each of the five quantities, while the Atlantic Ocean cold season has the lowest values in most categories. The higher values for the Indian Ocean may be due to its relatively high percentage of tropical coverage compared to the other two oceans. However, Q is found to increase faster for colder months from individual oceans, which differs from the general finding in the global Q - T relationship that Q increases slower for a colder climate. The modified relationship may be attributed to a possible seasonal （warm and cold） variability in boundary layer depth over oceans, or to the small sample size used in each individual oceanic group.展开更多
Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998–2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. A...Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998–2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum ana展开更多
基金funds from the U. S. Na- tional Aeronautics and Space Administration under Grant NNG04GB89G the U. S. National Science Foundation under grant ATM-0129495
文摘The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO4^2-, hydrophobic and hydrophilic black carbon （BC） and organic carbon compounds （OC）, including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion （especially in the aqueous phase） and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO4^2- shows less horizontal gradient and seasonality than SO2, with wet deposition （60%） and export （27%） being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition （60%） and export （30%）. The simulated spatial and seasonal SO4^2-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.
文摘An ideal and simple formulation is successfully derived that well represents a quasi-linear relationship found between the domain-averaged water vapor, Q （ram）, and temperature, T （K）, fields for the three tropical oceans （i.e., the Pacific, Atlantic and Indian Oceans） based on eleven GEOS-3 [Goddard Earth Observing System （EOS） Version-3] global re-analysis monthly products. A Q - T distribution analysis is also performed for the tropical and extra-tropical regions based on in-situ sounding data and numerical simulations [GEOS-3 and the Goddard Cumulus Ensemble （GCE） model]. A similar positively correlated Q - T distribution is found over the entire oceanic and tropical regions; however, Q increases faster with T for the former region. It is suspected that the tropical oceans may possess a moister boundary layer than the Tropics. The oceanic regime falls within the lower bound of the tropical regime embedded in a global, curvilinear Q - T relationship. A positive correlation is also found between T and sea surface temperature （SST）; however, for one degree of increase in T, SST is found to increase 1.1 degrees for a warmer ocean, which is slightly less than an increase of 1.25 degrees for a colder ocean. This seemingly indicates that more （less） heat is needed for an open ocean to maintain an air mass above it with a same degree of temperature rise during a colder （warmer） season [or in a colder （warmer） region]. Q and SST are also found to be positively correlated. Relative humidity （RH） exhibits similar behaviors for oceanic and tropical regions. RH increases with increasing SST and T over oceans, while it increases with increasing T in the Tropics. RH, however, decreases with increasing temperature in the extratropics. It is suspected that the tropical and oceanic regions may possess a moister local boundary layer than the extratropics so that a faster moisture increase than a saturated moisture increase is favored for the former regions. T, Q, saturated water vapor, RH, and SST are also examined with regard to the warm and cold ＂seasons＂ over individual oceans. The Indian Ocean warm season dominates in each of the five quantities, while the Atlantic Ocean cold season has the lowest values in most categories. The higher values for the Indian Ocean may be due to its relatively high percentage of tropical coverage compared to the other two oceans. However, Q is found to increase faster for colder months from individual oceans, which differs from the general finding in the global Q - T relationship that Q increases slower for a colder climate. The modified relationship may be attributed to a possible seasonal （warm and cold） variability in boundary layer depth over oceans, or to the small sample size used in each individual oceanic group.
基金the special grant from the National Natural Science Foundation of China (Grant No.40428002)the National Key Basic Research and Development Program of China (Grant No. 2004CB418303)
文摘Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998–2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum ana
