This report covers the ChinaMap activities related to Emissions which includes the efforts of David Streets at Argonne National Laboratory and Chip Levy at GFDL. This is an update to our report submitted prior to last November's ChinaMap Workshop held in Atlanta. The specific aspects of this report are: (1) the delivery of the newest versions of the NOx and SOx emission estimates for the years 1990, 1992/93, 1995 and 2000 on the ChinaMap grid; (2) delivery of CO and black carbon emissions for 1995 and 2000; and (3) Presentation of the soil dust emissions algorithm for use in on-line modeling analysis. Details are presented below.

The emission estimates for the targeted years have been completed for the ChinaMap study region. The China values are by fuel-use sector are presented in Figure 1 and Figure 2, and the gridded values are shown in Figure 3 and Figure 4. Complete details are presented in Draft Final Report #1.

2. CO Emissions for China in 1995 and 2020

A preliminary estimate of CO emissions for China in 1995 and 2020 has been completed. The emissions by sector are shown in Figure 5, and the gridded values are presented in Figure 6. Complete details are presented in Draft Final Report #2.

3. Black Carbon Emissions in China in 1995 and 2020

A preliminary estimate of CO emissions for China in 1995 and 2020 has been completed. The emissions by sector are shown in Figure 7, and the gridded values are presented in Figure 8. Complete details are presented in Draft Final Report #3.

The grid data can be downloaded here.

Wind blown soil emissions can be modeled based on the work of Gillette and Passi, 1988.The basic algorithm is shown in Figure 9. In this model the mass flux of dust into the atmosphere occurs when the surface friction velocity exceeds the threshold surface friction velocity (which is a function of soil and surface properties). An example of how this model has been used in studies in China is shown in Figures 10 and Figures 11, where the emissions are derived using ECMWF fields.

In order to calculate the dust emissions, it is necessary to estimate the threshold friction velocity (U_*^t ) for the soil types of China. The soil types were simplified to 5 main soil categories. Then according to these main soil catogeries, an aerodynamic roughness height, z₀ was assigned, the U_*^t was then determined from Figure 12

In general, the values of aerodynamic roughness height, z₀, reflect the visual appearance of roughness. Extremely small z₀ correspond to flat and almost polished clay surfaces. The z₀ values of the five soil categories values range from 0.0001 to 0.1, and z₀ increases from those of fine sand and smooth crusted soils to gravelly sand soil and rough clay crusted soils. The values used as z₀=0.0001, 0.001, 0.0032, 0.01 and 0.2 cm for the five main soil categories. Figure 1 shows that when z₀=0.0001, disturbed hilly soils have a U_t ^*=20cm/s; when z₀=0.001, loose sandy soils have a U_t ^* =30cm/s; when z₀=0 .0032, disturbed gravel soils have a U_t ^*=50cm/s; when z₀=0.01, crust soils have a U_t ^*=100cm/s; when z₀=0.2, soils with vegetation have a U_t ^*=250cm/s.

The base soil map used in the analysis is shown in Figure 13. These soils were then assigned a surface roughness and threshold velocities estimated. The map of threshold velocities is presented in Figure 14. The actual emissions depend upon the state of the surface as well. The presence of standing vegetation as well as recent precipitation will reduce the potential for wind blown emissions. The standing vegetation can be estimated by the use of satellite greenness data (Jing --ref or web site needed). Greenness map for the month of May is shown in Figure 15. Combining the greenness maps with the threshold velocity maps, provides a seasonal picture of potential source areas as in Figure 16. If the surface is dry then this information can be used on-line with a meteorological model to derive emission rates. To determine the dryness state of the soils one needs additional information such as time since the grid cell last received precipitation (or soil moisture).

The gridded fields at 1° by 1° resolution are shown in Figures17,   18,   19. For some applications, it is useful to have chemical composition as well as mass flux. We have also prepared soil chemistry maps, for example, calcium (Figure 20). The weight percent calcium can be used along with the dust emissions equation.

1.Dale A. Gillette, John Adams, Danel Muhs and Rolf Kihl, Threshold Friction Veolocities and Rupture Moduli for Crusted Desert Soils for the Input of Soil Particles into the Air, Journal of Geographical Research, Vol. 87, No. C11, Page 90003-905, Oct. 20, 1982.

2.Beatrice Marticorena, Gilles Bergametti, Dale Gillette, Jayne Belnap, Factors controlling threshold friction velocity in semiarid and arid areas of the United States, Journal of Geographical Research, Vol. 102, No. D19, Page 23277-23287, Oct. 20, 1997.