yang zhang - Academia.edu (original) (raw)

Papers by yang zhang

CarTel is a mobile sensor computing system designed to collect, process, deliver, and visualize d... more CarTel is a mobile sensor computing system designed to collect, process, deliver, and visualize data from sensors located on mobile units such as automobiles. A CarTel node is a mobile embedded computer coupled to a set of sensors. Each node gathers and processes sensor readings locally before delivering them to a central portal, where the data is stored in a database for further analysis and visualization. In the automotive context, a variety of on-board and external sensors collect data as users drive.

Journal of Geophysical Research, 2001

Journal of Applied Meteorology, 1994

Journal of Geophysical Research, 2001

A variety of measurements have been used to evaluate the treatment of aerosol radiative propertie... more A variety of measurements have been used to evaluate the treatment of aerosol radiative properties and radiative impacts of aerosols simulated by the Model for Integrated Research on Atmospheric Global Exchange (MIRAGE). The treatment of water uptake in MIRAGE agrees with laboratory measurements, and the growth of aerosol extinction with relative humidity in MIRAGE simulations agrees with field measurements. The simulated frequency of relative humidity near 100% is about twice that of analyzed relative humidity. When the analyzed relative humidity is used to calculate aerosol water uptake in MIRAGE, the simulated aerosol optical depth agrees with most surface measurements after cloudy conditions are filtered out and differences between model and station elevations are accounted for, but simulated optical depths are too low over Brazil and central Canada. Simulated optical depths are mostly within a factor of 2 of satellite estimates, but are too high off the east coasts of the United States and China and too low off the coast of West Africa and in the Arabian Sea. The simulated single-scatter albedo is consistent with surface measurements. MIRAGE correctly simulates a larger Ångström exponent near regions with emissions of submicron particles and aerosol precursor gases, and a smaller exponent near regions with emissions of coarse particles. The simulated sensitivity of radiative forcing to aerosol optical depth is consistent with estimates from measurements. The simulated direct forcing is within the uncertainty of estimates from measurements in the North Atlantic.

Journal of Geophysical Research, 1996

Journal of Geophysical Research, 1998

Ozone transport and chemistry in the springtime in east Asia are studied by use of the STEM-II (S... more Ozone transport and chemistry in the springtime in east Asia are studied by use of the STEM-II (Sulfur Transport Eulerian Model) regional-scale transport/chemistry model. Three-dimensional simulations are performed for the period May 115, 1987. This was a period of strong ...

Atmospheric Environment, 1996

A preliminary assessment of the seasonal variation in chemical composition of aerosols measured a... more A preliminary assessment of the seasonal variation in chemical composition of aerosols measured at Cheju Island, Korea, is presented. Weekly and monthly averaged aerosol composition derived from 15 months of daily filter measurements are presented. The annual-average non-sea-salt sulfate and nitrate mass concentrations of aerosols measured at Cheju are found to be 6.9 pg me3 and 1.2 pgrnm3, respectively; calcium and potassium are present in nearly equal quantities at _ 0.5 pgrne3, and ammonium averaged 1.4 pg rnm3. Each species is found to follow a seasonal cycle with sulfate, nitrate, ammonium, potassium and calcium all showing up to 50% higher values in the spring. In contrast, chlorine is 30% lower in the spring. Aerosol enrichment factors relative to the composition of seawater and crustal material from the Gobi dust-source region in China are also presented. The aerosol measured at Cheju is found to be enriched in sulfate, nitrate and ammonium, but deficient in chlorine (relative to seawater). These results along with modeling studies suggest that the dust surfaces play an important role in nitrate and sulfate formation.

Journal of Applied Meteorology, 1999

A detailed gas-phase chemistry mechanism is combined with dust surface uptake processes to explor... more A detailed gas-phase chemistry mechanism is combined with dust surface uptake processes to explore possible impacts of mineral dust on tropospheric chemistry. The formations of sulfate and nitrate on dust are studied along with the dust effects on the photochemical oxidant cycle for the long-range-transported particles with a diameter of 0.1-40 m.