Surface Air Temperature Variability over Subregions of Pakistan During 1970-2014

Karim, Rizwan

PURE AND APPLIED GEOPHYSICS

2023

180

11

Tan, GR

This study examines seasonal and annual mean temperature changes from 1970 to 2014. Climatologically, the June-July-August season exhibited the highest (27 degrees C) mean temperatures over the country, followed by March-April-May (MAM; 20.2 degrees C), September-October-November (SON; 19.1 degrees C), and December-January-February (DJF; 8.8 degrees C), while the annual mean was 18.8 degrees C. The southern region exhibited higher mean temperatures than the northern region for the DJF, MAM, JJA, SON, and annual timescales during the study period. The seasonal trend across the country was highest in MAM (0.027 degrees C/year), followed by SON (0.025 degrees C/year), DJF (0.023 degrees C/year), and JJA (0.016 degrees C/year). The interannual trend increased significantly at 0.023 degrees C/year across the country. Across the north, MAM showed the highest increase (nonsignificant) in trends at 0.025 degrees C/year, followed by a significant increase during SON (0.018 degrees C/year), DJF (0.017 degrees C/year), and JJA (0.010 degrees C/year), while annual trends were the lowest (0.017 degrees C/year). Examination of abrupt change over Pakistan showed nonsignificant change during JJA, while MAM, JJA, SON, and annual timescales demonstrated significant positive and negative changes. Decadal anomalies showed long-term positive tendencies in DJF (since 1990-2014) temperature, followed by JJA, SON, annual, and MAM timescales (2000-2014). In conclusion, the observed changes in temperature were significantly robust and promise increasing signal patterns in all time scales.