Long-Term Spatial and Temporal Trends in Warm (cold) Spells, Wet (dry) Spells in Kansas, USA.

Long-term spatial and temporal trends in warm (cold) spells, wet (dry) spells in Kansas, USA Aavudai Anandhi, Hamze Dokoohaki Abstract Warm spell indices such as Warm Spell Days (WSD), Average Warm Spell Days (AWSD), Warm Spell Duration Index (WSDI) and Cold spell indices such as Cold Spell Days (CSD), Average Cold Spell Days (ACSD) were calculated using daily air temperatures. Wet spell indices such as Average Wet Spell Length (AWSL) and Consecutive Wet Days (CWD); dry spell indices such as Dry Spell Length (ADSL) and Consecutive Dry Days (CDD) were calculated using daily rainfall (RF) from 23 centennial weather stations across Kansas during four time periods (through 1919, 1920–1949, 1950–1979, and 1980–2009). Studies have defined a warm day as one where maximum temperature > TX90 and a cold day as one where minimum temperature < TN10. TX90 and TN10 represent the 90th percentile of daily maximum temperature and 10th percentile of daily minimum temperature in the time period (1971-2000). A wet day is defined as a day with precipitation > 1 mm and a dry day is defined as one where precipitation is < 1 mm. The long- and short-term trends in these indices were analyzed at monthly, seasonal, and annual timescales. Preliminary results indicated a general increase in temperature from 1900 through 2009 causing changes in the indicators. 1