Presentation on theme: "Centre for Atmospheric Sciences Indian Institute of Technology Delhi Hauz Khas, New Delhi – 100 016 S K Dash Some Evidences of Climate Changes in India."— Presentation transcript:
Centre for Atmospheric Sciences Indian Institute of Technology Delhi Hauz Khas, New Delhi – 100 016 S K Dash Some Evidences of Climate Changes in India which may be used for Model Verifications
The Main Topics of Discussion are : Meteorological Parameters Extreme Weather Events Water Availability Ecosystems Coastal Zone Studies Wildlife Health Medicinal Plants Desertification Glaciers Mitigation Strategies
Meteorological Parameters : Long term observed data show that the maximum temperature over India has increasing trend whereas the minimum temperature does not show any definite changing pattern. The Indian summer monsoon rainfall does not show any definite increasing/decreasing trend which can be attributed to global warming. There are evidences of winter/spring rainfall increase and monsoon rain decrease in the Doon valley during the last 70 years.
Analysis of observed data from 1891-1997 shows increase in the number of extra-tropical cyclones/winter-storms, but decrease in tropical cyclones. Also pre-monsoon and post- monsoon cyclones increase in number Extreme Weather Events : The monsoonal disturbances such as number of lows, depressions, cyclones or severe cyclonic storms do not show any definite increasing/decreasing trend. However it is necessary to examine the occurrence of only the extreme weather events such as heat wave conditions, severe cyclonic storms or super-cyclones vis-à- vis the climate change.
Figure 1 Highest maximum temperature recorded at some stations of Andhra Pradesh and Orissa during heat wave (May 19 - June 10, 2003).Stations considered are Ongole (ONG), Kakinada (KND), Machillipatanam (MPT), Gannavaram (GNV), Nellore (NLR) Titilagarh (TTG), Hanumankunda (HNK).
Figure 2 Highest maximum temperature recorded at some stations during heat wave of Andhra Pradesh in May & June 2003 and the earlier recorded highest maximum temperature.
Figure 3 Highest maximum temperature recorded at some stations during heat wave of Orissa in May & June 1998 and the earlier recorded highest maximum temperature.
Figure 4 Percentage frequencies of number of days with horizontal visibility < 2000 m at 0300 UTC during winter season with significant trends at 99% level. De et al (2001).
Figure 5 Variation of the number of fog days in the month of January for 1989 to 2003 at New Delhi and the corresponding 5-year running mean values.
Figure 6 Trends of average duration of visibility (hrs / day) < 200 meters for 1964 to 1998 at Delhi. Source: Singh (2001).
Figure 7 Percentage deparature of Indian summer monsoon rainfall from its mean value for 1900 to 2003 and running mean values over different periods.
Figure 8 Percentage of area of the country under moderate and severe drought for the period 1877-2002.
Figure 9 Eleven year running means of annual frequency of disturbances with the minimum intensity of depressions and cyclonic storms formed over he Indian region (1891- 2003).
Figure 10 Eleven Year running means of frequency of monsoon depressions formed during June to September (1889-2003).
Figure 11 Eleven year running means of frequency of disturbances with the minimum intensity of cyclonic storms formed in the months of May, October & November (1891-2003).
Figure 12 Eleven year running means of frequency of disturbances with the intensity of depressions and above formed in the months May, October and November during 1891-2003.