Research |
Transport of air pollutants over the Indian RegionThe computed temperature data is compared with the measured data of Delhi (personal communication) for December 24 to 30, 2002 at different times of the day with a three-hour interval. The latitude and longitude for Delhi are 28.45° N and 77.02° E. In a 91 x 91 grid as shown in figure 2, Delhi is covered between the latitudes 28.10° N and 28.58° N and longitudes 76.83° E and 77.37° E. In a 181 x 181 grid, Delhi (28.45° N and 77.02° E) is covered between the latitudes 28.23° N and 28.46° N and longitudes 76.83° E and 77.37° E. Figure 3 shows a plot of three temperature series starting from December 24, 2002 at 21:00 hrs. (GMT) or 2:30 PM (IST) to December 31, 2002 at 12:00 hrs (GMT) or 5:30 AM (IST) with three hour increment in time. As seen from these graphs, the computer model over estimates the temperature. Difference between computed and measured temperature ranges from 0.5 degree to 5 degrees. A few times, the difference becomes 10 degrees. This difference can be attributed to the influence of the initial conditions. Series 1 (measured data) compares better with series 3 (model with a 30 km resolution) than with the series 2 (model with a 60 km resolution). Figure 3: (Comparison of temperature over Delhi for December 24 to 30, 2002) Series 1: Measured temperature at New Delhi Series 2: Computed temperature with 91 x 91 grid for Delhi at grid location Series 3: Computed temperature with 181 x 181 grid for Delhi at grid location This difference in the temperature is within the acceptable range. The model is run for the month of February 2000. Figure 4 shows the temperature variation over Delhi with a three-hour time interval in February 2000, as obtained from model run.
Figure 4: (Temperature variation over Delhi in February 2 – 29, 2000)
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