Province based analysis of observed climate indices suggests some substantial increases and decreases in the trends over the baseline period. Station based analysis indicates significant trend changes at some stations while insignificant trend changes at others over each province. Although climatic features are not bounded by administerial or political boundaries, yet the selected administerial bounded regions somewhat describes distinct climatic features and hence are used for province based analysis.
Observed indices of GB-AJK
Upon the analysis of Cold spell duration indicator it is seen that no significant change has occurred over the past 54 years (Figure 5.1). General trend is increasing but is not statistically significant. Consecutive wet days in AJK and GB has displayed a contrast in the trend observation of the index. The stations at GB (Gilgit, Gupis and Skardu) tend to display an insignificant increasing trend whilst the stations at AJK tend to show significantly decreasing trend. The decreasing trend of consecutive wet days in Kotli is six days while that in Muzaffarabad is three days with confidence at 99% level. In AJK and GB, the DTR show statistically significant increasing trend over the past 54 years. In GB, Gilgit displays a DTR trend increase of 2.2°C, Gupis displays that of 3°C, and Skardu displays that of 3.1°C over the past 54 years. In AJK, Kotli displays a DTR trend increase of 1.2°C, and Muzaffarabad displays that of 1°C over the past 54 years. A general increasing trend is observed in the analysis of frost days trend in AJK and GB. In GB, Gupis displays a frost days increasing trend of 21 days with 98% confidence, and Skardu displays a frost days increasing trend of 10 days with confidence of 92% over the 1960-2013 past 54 years period. Gilgit displays no change in its trend of frost days index. In AJK, the trend tends to be increasing but with smaller confidence and smaller number of days increasing over the historical period.
Ice days index when TMAX is less than a temperature threshold, indicates a general decreasing trend in AJK and GB. In GB, the ice days in Gilgit has decreased by 19 days, in Gupis by 21 days, and in Skardu by 30 days at 99% level of significance over the historical period of 1960-2013. In AJK, no significant trend is observed over the analysis of ice days index in past data. Heavy precipitation days for GB have been identified as those in which PR > 10 mm, while heavy precipitation days for AJK have been identified as those in which PR > 20 mm. In case of GB, Gupis displays a statistically significant (at 99% level) increasing trend of 6 days, while Skardu displays an increasing trend of 4 days at 93% level over the past 54 years. Giglit displays no significant trend in the number of heavy precipitation days over the historical analysis. In case of AJK, Kotli displays a statistically significant increasing trend of the heavy precipitation days with an increment of 6 days, and Muzaffarabad displays a statistically significant increasing trend of the heavy precipitation days with an increment of 18 days over the historical period of 1960-2013. Very wet days precipitation when annual total PRCP>95th percentile displays generally an increasing trend in AJK and GB over the past 54 years. Statistically significant increasing trend at 99% level is observed in Kotli and Muzaffarabad which shows that the annual total precipitation for very wet days has increased by 225 mm and by 432 mm respectively over the historical 1960-2013 historical period. No significant trend is observed in regions of GB probably owing to some very heavy precipitation years taken inclusive.
Monthly maximum consecutive 5-day precipitation amount in stations of AJK have shown significant increase with 48 mm in Kotli (at 90% level) and with 96 mm in Muzaffarabad (at 99% level). However, over GB, no significant change in the monthly maximum consecutive 5-day precipitation amount is identified upon the analysis of the historical data. Increase in 5-day consecutive precipitation may lead to Glacier lake outburst flooding in the Northern areas of Pakistan. Summer days when annual count of daily maximum temperature >25ºC displays an increasing trend in AJK and GB. In GB, Gilgit displays an increasing trend of 24 days with 99% level of confidence, Gupis displays an increasing trend of 15 days with 95% level of confidence, and Skardu displays an increasing trend of 27 days with 99% level of confidence over the past 54 years. In AJK, Kotli displays an increasing trend of 13 days with 90% level of confidence, and Muzaffarabad displays an increasing trend of 17 days with 95% level of confidence. In AJK and GB, there is an increasing trend in the number of cool nights in all the stations taken, however none of the stations give significance at 95% level. In AJK and GB, a decreasing trend of warm nights is observed over the analysis of the 1960-2013 historical period. The decreasing trend is significant at 99% level for Gilgit (7 days decrease), Gupis (17 days decrease), and Kotli (9 days decrease). No significant trend is observed in Muzaffarabad and Skardu in the analysis of warm nights.
Tropical nights calculated by setting annual count when TN(daily minimum)>20ºC display decreasing trends in the AJK and GB. The decreasing trend of GB is significant at 99% level. In GB, Gilgit displays a rate of decrease of 16 nights per 53 years, Gupis displays a rate of decrease of 6 nights per 53 years, and Skardu displays a rate of decrease of 8 nights per 53 years. There is no significant trend displayed by Kotli and Muzaffarabad. In GB, there is a significant decrease in the trend of cool days. In Gilgit, there is a decrease of 7 days at 99% level, in Gupis, there is a decrease of 5 days at 90% level, and in Skardu, there is a decrease of 12 days at 99% level. No significant change in the trends of cool days in Kotli and Muzaffarabad is observed in the past 54 years. Warm days calculated by the percentage of days when TX>90th percentile displays an increasing trend in AJK and GB over the analysis of the 1960-2013 historical period. In Gilgit, there is a significant increasing trend of 11 days at 99% level, in Gupis, there is a significant trend of 7 days at 95% level, and in Skardu, there is a significant increasing trend of 13 days at 99% level over the past 54 years. In AJK, Muzaffarabad displays a significant increasing trend of 9 warm days with confidence of 99% over the past data analysis. Kotli, however, displays no significant trend observation in case of warm days index. There is a general increasing trend in the warm spell duration indicator over AJK and GB. Skardu in GB show relatively higher confidence in displaying 11 days increase in the warm spell duration index over the past 54 years. The index is of vital significance since major GLOF events are effects of prolonged heat waves over the region.
Observed indices of KPK
In KPK, cold spell duration index has a general decreasing trend which means that cold waves have decreased over the past in KPK. In DI Khan and Peshawar, a linear trend decrease of 15 days (significant at 95% level) and 7 days (significant at 93% level) respectively in the cold spell duration index, is observed upon the analysis of past 54 years data (Figure 5.2). Slope estimate of Dir is not statistically significant, while Parachinar displays a statistically significant increasing trend of 33 days in the cold spell duration indicator upon the analysis of past 54 years data. No statistically significant trends are observed in consecutive wet days in KPK over the 1960-2013 past data analysis. Diurnal temperature range in KPK show clear signals increasing trends over the past 54 years data analysis. The stations at Dir, Parachinar, and Cherat show high confidence in increasing trends with 2.2°C, 3.1°C, and 2.5°C respectively at 95 % level. On the other hand, diurnal temperature ranges of DI Khan and Peshawar show a decreasing trend but with smaller confidence and smaller statistical significance. Upon the analysis of frost days in KPK, the annual count of days with minimum temperature < 0.0°C taken as a threshold, gives no significant trend over the analysis of the past 54 years data. However, one station, Parachinar gives a statistically significant (at 99 % level) trend of 62 days increase in the frost days index. This substantial increase is displayed in Parachinar after 1980 which continues to remain so till 2013. Also the frost days with specified thresholds, show significant trends in KPK for the past 54 year data analysis. Frost days in Parachinar with minimum temperature below -4°C show a significant increasing trend at 99 % level with slope estimate of 65 days increase over the past 54 years data. On the other hand, DI Khan and Peshawar show statistically significant decreasing trends of 16 days and 14 days respectively, both at 99% level of confidence. Dir and Cherat show no statistically significant change in the trends of frost days index.
In the past data analysis, annual total precipitation amount of DI Khan and Peshawar has significantly increased in KPK. In DI Khan, the total precipitation has increased by 148 mm, and in Peshawar, the total precipitation has increased by 263 mm, over the past 54 years (significance of trend is at 99% level). However, there is no significant trend observed in total precipitation of Dir, Parachinar and Cherat over the last 54 years. Heavy precipitation extremes of rainfall > 10 mm display significant increase in the number of days in DI Khan and Peshawar, with an increase of 4 days (significant at 95 % level) and an increase of 9 days (significant at 99 % level) over the past 54 years. Dir, Parachinar and Cherat show high variability with no significant trend observed in the number of days with heavy precipitation events. Very heavy precipitation events defined by annual count of days when PRCP>=20mm have significantly increased in DI Khan and Peshawar with slope estimates of 3 days and 6 days respectively, both significant at 99 % level of confidence. Once again Dir, Parachinar and Cherat does not show any significant trend in the very heavy precipitation days over the past 54 years data analysis. Annual total precipitation of very wet days when rainfall > 95th percentile displays a significant increasing trend in DI Khan and Peshawar of KPK. There is 91 mm increase in the total precipitation of very wet days in DI Khan (95% confidence level), and 123 mm increase in the total precipitation of very wet days in Peshawar (99% confidence level) over the analysis of past 54 years data. No significant trend in the annual total precipitation of very wet days is observed in the past data analysis of Dir, Parachinar and Cherat. Monthly maximum 5 day consecutive rainfall trend displays significant trend with 82 mm increase in Dir (at 95 % level) and with 61 mm increase in Peshawar (at 95 % level) over the analysis of past data over KPK. No statistically significant trend is observed in Parachinar, DI Khan and Cherat in the monthly maximum 5 day consecutive rainfall trend over the past data analysis.
Summer days index when the maximum temperature > 25°C displays a statistically significant trend towards increasing in Peshawar city of KPK province over the past 54 years data analysis. The trend shows an increase of 23 days in the past 54 years in Peshawar with significance at 99 % level. However, no other station of KPK show statistically significant trend in the summer days index. Summer days index with maximum temperature > 32°C has high confidence in the increasing trend of Dir in KPK. Summer days index trend in Dir has displayed an increase of 41 days over the past 54 years data analysis. The confidence over the increasing trend in Dir is at 99 % level. Mean of maximum temperature over the past 54 years data display a high confidence in the increasing trends of Dir and Peshawar of KPK. Dir displays 1.5°C increase, while Peshawar displays 0.9°C increase in the mean of the maximum temperature over the last 54 years. Trend of the mean of the minimum temperature over Parachinar in KPK show a significant decreasing trend of 3.3°C, while that over Peshawar in KPK show a significant increasing trend 0.9 of°C over the past 54 years data analysis. Both the trends are significant at 99 % level of confidence. Cool nights in Parachinar of KPK display an increasing trend of 20 nights with significance at 99 % level. On the other hand both DI Khan and Peshawar display decreasing trends of 5 nights and 6 nights significant over 95 % and 99 % level in the past 54 years. No significant trend is displayed by Dir in the trend of cool nights.
General trend of warm nights is decreasing in KPK with the exception of Peshawar whose trend is significantly increasing over the past 54 years. The rate of increase in 54 years is 8 nights with confidence at 99 % level. DI Khan on the other hand displays a significant decreasing trend of 4 nights in the past 54 years over KPK. Tropical nights in Dir and Cherat display significant decreasing trend while those in DI Khan and Peshawar display significant increasing trends. Tropical nights trend in Dir displays 19 nights decrease at 95 % level, and that in Cherat displays 42 nights decrease at 95 % level over the past 54 years. On the other hand, tropical nights trend in DI Khan displays 14 nights increase at 95 % level, and that in Peshawar displays 18 nights decrease at 99 % level over the past 54 years. There is a general decreasing trend observed in the cool days index of KPK over the past 54 years. Statistically significant trend is observed in Peshawar with 3 days increase in the cool days index with 99 % level of confidence. The general trend of warm days in KPK is increasing over the past 54 years data analysis. The rate of change is significant in Dir of KPK which displays an increase of 14 days over the past 54 years with confidence level at 99 % over the past 54 years. Warm spell duration index in KPK show generally an increasing trend which identifies the occurrences of heat waves in the region. Statistically significant increasing trends of 15 days in Dir and of 11 days in Parachinar are observed in the past 54 years data analysis of warm spell duration indicator in KPK.
Observed indices of Punjab
Cold spell duration indicator displays a general decreasing trend in Punjab over the analysis of past 54 years (Figure 5.3). Cold spells have decreased in Islamabad by 17 days at 99 % level, by 15 days in Sialkot at 90 % level, by 42 days in Lahore at 99 % level, by 19 days in Multan at 99 % level, by 33 days in Bahawalnagar at 99 % level, and by 13 days in Khanpur at 90 % level. Consecutive wet days in Punjab displays no significant trend, however Khanpur displays a statistically significant increase of 1 day (at 95 % level) in the maximum number of consecutive days with precipitation greater than 1 mm over the past 54 years analysis. DTR in Punjab displays a clear signal of decreasing trend in all the stations with statistically significant decreases of 1.5°C in Sialkot (at 99 % level), of 3.1°C in Lahore (at 99 % level), of 2.1°C in Multan (at 99 % level), and of 1.7°C in Khanpur (at 99 % level), over the past 54 years. There is a general decreasing trend in the number of frost days over the past 54 years in Punjab. Frost days has decreased by 7 days in Islamabad (at 95 % level), by 2 days in Lahore (at 95 % level), by 3 days in Multan (at 95 % level), and by 2 days in Bawalnagar (at 95 % level) in the past 54 years. In Punjab, the total precipitation has a significantly increasing trend in Bahawalnagar (162 mm in 54 years at 95 % level) and in Khanpur (84 mm in 54 years at 95 % level). In Punjab, there is a general increasing trend in the number of days with heavy precipitation. Significant trends are observed in Lahore and Bahawalnagar with 6 days increase in past 54 years at 95 % level of confidence. The number of days with very heavy precipitation also displays a general increasing trend in the past 54 years data analysis. Significant trend is observed in Bahawalnagar with 3 days increase at 95 % level.
Annual total precipitation amount of heavy precipitation events in Punjab show increasing trends in Islamabad, Lahore, Bahawalnagar, and Khanpur, while they show decreasing trends in Sialkot and Multan. Statistically significant increase in the annual total precipitation amount of heavy precipitation events is observed in Khanpur (70 mm in 54 years at 95 % level). Total precipitation amount of very heavy precipitation events in Punjab has displayed increasing trends in Islamabad, Lahore and Bahawalnagar, while it has shown decreasing trends in Sialkot and Multan. Significant trends are observed in the total precipitation amount of very heavy recipitaion events in Islamabad with 112 mm increase and in khanpur with 42 mm increase, both at 95 % level over the past 54 years analysis. 5 day consecutive precipitation amount in Punjab has displayed significant increase in Khanpur with 70 mm increase at 95 % level of confidence. Summer days with maximum temperature > 25°C in Punjab display altogether an increasing trend. Statistically significant trends are observed in Islamabad (20 days increase at 99 % level), in Sialkot (15 days increase at 95 % level), and in Multan (14 days increase at 95 % level) over the past 54 years analysis. Summer days with maximum temperature > 40°C in Lahore displays a significant decreasing trend, while summer days in Bahawalnagar with maximum temperature > 42°C displays a significant increasing trend over the analysis of past 54 years data analysis. The trend in Lahore is 11 days decrease with significance at 95 % level, whereas the trend in Bahawalnagar is 17 days increase with significance at 95 % level.
There is a statistically significant trend observed in the mean of the maximum temperature of Islamabad with increase of 1°C over the past 54 years. Mean of minimum temperature in Punjab is displaying altogether a significant increasing trend in all the observed stations. In Islamabad, it displays a trend of 1.1°C increase, in Sialkot, it displays a trend of 1.8°C increase, in Lahore, it displays a trend of 2.6°C increase, in Multan, it displays a trend of 2°C increase, in Bahawalnagar, it displays a trend of 2.2°C increase, and in Khanpur, it displays a trend of 1.6°C increase, all significant at 95 % level over the past 54 years. Cool nights in Punjab display a significantly decreasing trend altogether with 11 % decrease in Islamabad, 14 % decrease in Sialkot, 23 % decrease in Lahore, 13 % decrease in Multan, 19 % decrease in Bahawalnagar, and 11 % decrease in Khanpur, all confident over 95 % level. Warm nights in Punjab have altogether an increasing trend over the past 54 years analysis. The warm nights has increased in Islamabad by 5 %, in Sialkot by 14 %, in Lahore by 18 %, in Bahawalnagar by 16 %, and in Khanpur by 11 %, all significant at 95 % confidence level. Monthly minimum value of daily minimum temperature display over all an increasing trend over the past 54 years analysis. Significant trends are observed in Lahore (4.3°C increase), in Multan (3.1°C increase), in Bahawalnagar (2.7°C increase), and in Khanpur (2.1°C increase), at 95 % level of confidence. Monthly maximum value of daily minimum temperature in Punjab show variable trends. However significant trends are observed in Lahore (1°C increase), and in Multan (1°C decrease), both with confidence at 95 % level over the past 54 years.
The trends in tropical nights over Punjab display a statistically significant increase in the past 54 years of data. Tropical nights have increased in Islamabad with 22 nights, in Sialkot with 4 nights, in Lahore with 35 nights, in Multan with 18 nights, in Bahawalnagar with 35 nights, and in Khanpur with 23 nights, all significant at 99 % level of confidence. Cool days are decreasing significantly in Islamabad at the rate of 5 days in 54 years significant at 95 % level. Warm days in Islamabad are significantly increasing in Islamabad (6 days in 54 years), and Bahawalnagar (9 days in 54 years) while they are decreasing in Lahore (6 days in 54 years), significant at 95 % level. Monthly minimum value of daily maximum temperature displays a decreasing trend in Punjab with significant decrease in Sialkot (3.1°C), in Lahore (2°C), in Multan (3.8°C), and in Bahawalnagar (5°C), over the last 54 years. Monthly maximum value of daily maximum temperature displays an increasing trend in Punjab. Statistically significant trends are observed in Multan (1.4°C increase), in Bahawalnagar (2°C increase), and in Khanpur (1.2°C increase), all confident at 95 % level. Warm spell duration indicator displays decreasing trends in Sialkot, Lahore, Multan and Khanpur, while it displays increasing trends in Islamabad and Bahawalnagar. However, the trends of both increasing and decreasing warm spell duration are insignificant at both 99 % and 95 % level.
Observed indices of Sindh
The monthly mean difference between the maximum temperature and the minimum temperature i.e. the diurnal temperature range (DTR) exhibits two distinct trends in the analysis. One of the trends is decreasing with significance at 99% and 95% for Badin and Karachi respectively, that are along the coast (Figure 5.4). The rate of decrease over the past 54 years (1960-2013) has been estimated to be 0.04°C per year for Badin and 0.01°C for Karachi. On the other hand, an increasing trend of 0.01°C in Chhor, and of 0.03°C in Nawabshah with significance at 91% and 99% respectively is also observed. This signals a significant increase of DTR in the internal Sindh and a significant decrease of the same along the coastal areas of Sindh. Annual total wet-day precipitation in Sindh does not show any significant linear trend over the past 54 years. There is an insignificant increasing trend observed from 1960-1980, then an insignificant decreasing trend from 1981-2000, and then again an insignificant increasing trend onwards till 2013 for Badin, Karachi, and Nawabashah. However, in Chhor, an increasing trend of 2.3 mm/year is observed with confidence of 86% which indicates that Chhor has received an estimated 150 mm more rain over the past 54 years from 1960-2013.
In Sindh, for maximum number of consecutive wet days, there is no significant increasing or decreasing trend observed in Karachi, Chhor, Nawabshah, and Rohri over the past 54 years (1960-2013). However, a weak significant increasing trend at 92% level in Badin suggests an increase of 3 days in the maximum number of consecutive rainy days over the past 54 years. Annual count of heavy precipitation days with precipitation > 10 mm/day has no significant linear trend over Sindh when past 54 years (1960-2013) data is analysed. In Sindh there is an insignificant increasing linear trend in the annual count of heavy precipitation days from 1960 to 1980, then an insignificant decreasing linear trend from 1981 to 1995, and then once again an insignificant linear increasing trend from 1996 to 2013 and onwards. This indicates no significant change in the heavy precipitation trends over Sindh over the past 54 years. Annual count of days with very heavy precipitation in Sindh also displays an insignificant linear trend with an insignificant increase from 1960 to 1980, an insignificant decrease from 1981-1998, and an insignificant increase 1999 onwards till 2013. This indicates that heavy precipitation days with precipitation > 20 mm/day on annual basis has no significant trend observed in the past 54 years over the Sindh.
Annual total precipitation for very wet days (rainfall rate > 95th percentile) displays variable trends between the stations in Sindh, yet none of them are significant at 95% confidence level. In Badin, Rohri and Chhor, there is an insignificant increasing trend from 1960 to 1990, after which it starts decreasing insignificantly till 2013. Karachi and Nawabshah also displays insignificant linear trends for the past 54 years. In the recent years, from 1990 to 2013, Chhor has displayed a decrease of 100 mm in annual total of very wet days for the last 24 years. On the other hand Karachi has displayed a simultaneous increase of 100 mm in the annual total precipitation for very wet days over the recent past. Annual total precipitation for extremely wet days over Sindh displays insignificant linear trends over the past 54 years (1960-2013). Insignificant increasing trends are observed in Badin (0.36 mm/year) and in Rohri (0.67mm/year). Nevertheless statistically significant (at 95% level) increasing linear trend is observed in Chhor, which indicates 1.2 mm/year rise in the annual total precipitation amount for extremely wet days over the last 54 years. Analysis of the monthly maximum consecutive 5-day precipitation over Sindh has displayed majorly insignificant trends over the past 54 years. However, for Chhor, it is seen that the index has displayed a statistically significant (at 95% level) increase over the past 54 years. The rate of increase is 1.7 mm/year which approximately amounts to 90 mm increase in the monthly maximum 5-day precipitation over Chhor in the past 54 years. Simple daily intensity index calculated by the annual total precipitation divided by the number of wet days displays an insignificant decreasing linear trend in Badin, whilst it displays an insignificant increasing linear trend in Rohri over the past 54 years over Sindh. Badin displays a straight away decreasing trend with the exception of 1980 to 1995 where it represents that higher amount of precipitation fell over few wet days. In case of Rohri, though the trend is decreasing, yet the 1980 to 1985 high intensity signal is again visible which displays anomalous high precipitation amount in smaller number of days.
Summer days in which maximum temperature is > 25°C is an important index to be analyzed for humid regions like Sindh, since even a degree Celsius rise in humid environment bring distress in the ambient temperature over the region. The region displays statistically significant increase (at 95% level) in Chhor, Karachi, Nawabshah and Rohri, with linear increasing trends of 11 days in Chhor, 26 days in Karachi, 20 days in Nawabshah, and 16 days in Rohri, over the past 54 years. Badin show a decreasing linear trend but is not significant at 95% level. Increase in summer days over Sindh province is statistically significant at 95% level in Chhor, Karachi, and Nawabshah, with linear trend increase of 19 days in Chhor (tmax > 42°C), 19 days in Karachi (tmax > 36°C), and 26 days in Nawabshah (tmax > 44°C). Badin displays a linear decreasing trend of 18 days (tmax > 39°C) which seems significant at 95% level, but not might be so, owing to the missing values between 1965 to 1975, and to the recent increase in the number of summer days after year 2000 till 2013. Rohri displays no significant change in its historical summer day evolution. In Sindh the mean of the maximum temperature over the past 54 years has shown a significant increase of 1.5°C in Chhor, 1.5°C in Karachi, and 1.7°C in Nawabshah over the past 54 years. Badin displays an insignificant linear trend with a decrease from 1960 to 1980, and then a continuous increase afterwards till 2013. Rohri also displays no significant linear trend over the past 54 years.
Increase in minimum temperature renders night time temperature to become warmer. Sindh has displayed significant increase in mean of the minimum temperature in Badin (1.6°C), and in Karachi (2.2°C). Chhor, Nawabshah, and Rohri does not show a significant linear trend, however, in the recent past (2000-2013), the stations display a warming trend in the mean of the minimum temperature. Sindh has displayed a statistically significant decrease in the percentage of cool nights in Badin and Karachi (both stations display 16.2% decrease at 99% level of confidence), and in Chhor (decrease of 6.5% at 86% level of confidence). No statistically significant linear trend is observed in the percentage change of cool nights in Nawabshah and Rohri. In Sindh, the analysis of past data has shown that Badin, Karachi, and Rohri has shown significant increase (at 99% level of confidence) in the number of days with warm nights. The rate of increasing trend in Badin is 10 days, that of Karachi is 16 days, and that of Rohri is 14 days over the past 54 years. There is no statistically significant change in the rate of warm nights of Chhor and Nawabshah, which indicates that the coastal areas (Karachi and Badin) have been more prone to endure increase in the warm nights over the past.
The monthly minimum value of daily minimum temperature in Sindh has displayed significant increasing trend in Badin, Chhor and Karachi with 99% level of confidence in the trend. There is an increase of 2.9°C in the monthly minimum value of daily minimum in Badin, of 2.6°C in the monthly minimum value of daily minimum in Karachi, and of 2.7°C in the monthly minimum value of daily minimum in Chhor. No significant trend is displayed in Nawabshah and Rohri. No significant trend is observed in the monthly maximum value of daily minimum temperature in Sindh. Tropical nights are annual count of days when daily minimum is greater than 20°C. In Sindh, the tropical nights have shown a statistically significant increasing trend at 99% level of confidence in Badin, Chhor, and Karachi. Tropical nights, on average, have been increased by 25 days in Badin, by 14 days in Chhor, and by 36 days in Karachi over the past 54 years. No significant trend is observed Nawabshah and Rohri. Percentage of days when maximum temperature exceeds 90th percentile, is referred to as warm days index. In Sindh, Chhor, Karachi, and Nawabshah display statistically significant increasing trend at 99% level with average increase of 9 days, 8 days, and 11 days respectively. Badin also displays a significant decreasing trend, however, owing the non-availablity of data from 1965-1975, the trend might be insignificant. Rohri shows an increasing trend significant at 80% level of confidence.
Monthly maximum value of daily maximum temperature in Sindh has shown, in general, increasing trend, with Chhor and Nawabshah being statistically significant at 95% and 99% respectively. Chhor displays an increase of 2.2°C (however, recent 15 years from 1998-2013 has shown a decrease), whereas Nawabshah displays an increase of 3.5°C in the monthly maximum value of daily maximum temperature over the past 54 years. In Sindh, Karachi and Nawabshah both display an increasing trend in warm spell duration index at 95% confidence level, while Rohri displays an increasing trend in the index at 83% confidence level. In Karachi, the warm spell duration has increased by six days, in Nawabshah by eight days, and in Rohri by five days over the past 54 years. Badin displays a significant decreasing trend but with smaller confidence owing to the missing values from 1965 to 1975. Chhor displays an increasing trend in the far historical period, yet it gets decreasing in the recent past. It is seen from the analysis that no significant change in the trend of cold spell duration index has occurred over the past 54 years. General trend is increasing but is not statistically significant.
Observed indices of Balochistan
Cold spell duration indicator in Baluchistan display significant decreasing trends in Quetta, Dalbandin and Panjgur (Figure 5.5). The decreasing cold spell in the last 54 years in Quetta is 36 days, in Dalbandin is 17 days, and in Panjgur is 15 days, all significant at 99 % confidence level. No statistically significant trend is observed in the consecutive wet days observed in all stations of Baluchistan. Statistically significant increasing DTR trends are observed in Baluchistan. In Zhob, the increasing trend is 2.2°C (at 95 % level), in Barkhan, the increasing trend is 3.4°C (at 99 % level), and in Dlabandin, the increasing trend is 0.8°C (at 95 % level), in the past 54 years. There are significant decreasing trends in the frost days of Baluchistan. Statistically significant decreasing trends are observed in Quetta (28 days at 95 % level), and in Dalbandin (18 days at 99 % level). Annual total precipitation amount has no significant trend observed in Baluchistan over the past 54 years. No significant trend in heavy and very heavy precipitation amount is observed in Baluchistan. Also no significant trend is observed in the very wet days of Baluchistan in the past 54 years. Moreover, no significant trend is observed in the extremely wet days of Baluchistan in the past 54 years. Furthermore, monthly maximum consecutive 5-day precipitation amount has no significant trend observed in Baluchistan over the last 54 years.
Summer days in Baluchistan display a significant increasing trend upon the analysis of last 54 years. In Zhob, there is a 26 days increase, in Khuzdar, there is a 36 days increase, in Quetta, there is a 29 days increase, in Barkhan, there is a 32 days increase, in Dalbandin, there is a 32 days increase, and in Panjgur, there is a 23 days increase, in the summer days over the last 54 years, all significant at 99 % level of confidence. Extreme summer days in Baluchistan also have a significant increasing trend. Summer days with maximum temperature > 36°C displays an increasing trend of 23 days in Quetta, those with maximum temperature > 43°C displays an increasing trend of 28 days in Dalbandin, and those with maximum temperature greater than 40°C displays an increasing trend of 16 days, over the last 54 years analysis. There is a significant increasing trend in the mean of the maximum temperature observed in Baluchistan. In Zhob, the increasing trend is of 1.4°C, in Khudar, the increasing trend is of 1.8°C, in Quetta, the increasing trend is of 2.1°C, in Barkhan, the increasing trend is of 1.4°C, in Dalbandin, the increasing trend is of 2.7°C, and in Panjgur, the increasing trend is of 1.4°C, over the last 54 years, all significant at 95 % level of confidence. Stations of Baluchistan display significant increase, except for Zhob and Badin (which show insignificant decrease) in the trends of mean of the minimum temperature index. Statistically significant trends of the index are observed in Quetta with 2.8°C increase, in Dalbandin with 1.6°C increase, and in Panjgur, with 1.4°C increase, over the last 54 years.
Cool nights display a significant decreasing trend in Quetta, Dalbandin, and Panjgur stations of Baluchistan. In Quetta, the index is decreased by 23 nights, in Dalbandin, the index is decreased by 10 nights, and in Panjgur, the index is decreased by 11 nights, over the past 54 years. Warm nights in Baluchistan display a significant increasing trend in Khuzdar, Quetta, and Panjgur stations. In Khuzdar, the index trend displays an increase of 15 nights, in Quetta, the index trend displays an increase of 9 nights, and in Panjgur, the index trend displays an increase of 6 nights, in the last 54 years. There is no significant trend observed in the monthly minimum value of daily minimum temperature in Baluchistan over the last 54 years. No significant trends are observed in the monthly maximum of minimum temperatures over Baluchistan in the past 54 years. However, Zhob displays a significant trend in the index with a decrease of 2.9°C at 95 % confidence level. Tropical nights display a significant increasing trend in Quetta (27 nights at 99 % level), in Dalbandin (28 nights at 99 % level), and in Panjgur (31 nights at 99 % level), over the past 54 years analysis.
Cool days are significantly decreasing all over Baluchistan. Zhob displays a decrease of 5 days, Khuzdar displays a decrease of 10 days, Quetta displays a decrease of 11 days, Dalbandin displays a decrease of 13 days, and Panjgur diplays a decrease of 7 days, significant at 95 % level, over the last 54 years. There is a statistically significant increase in the number of warm days in Baluchistan over the last 54 years data analysis. Increasing trends of the index are displayed in Zhob (8 days at 99 % level), in Khuzdar (10 days at 95 % level), in Quetta (12 days at 99 % level), Barkhan (10 days at 95 % level), in Dalbandin (16 days at 99 % level), and in Panjgur (9 days at 99 % level), over the last 54 years. No significant trends are observed in monthly minimum of the daily maximum temperature over Baluchistan in the last 54 years. Significant trends are observed in the monthly maximum of the daily maximum temperature over Baluchistan. Quetta displays 1.5°C increase in the index, and Dalbandin displays a 2.4°C rise in the index, both significant a t 99 % level, over the past 54 years. Warm spell duration indicator displays increasing trends over Baluchistan. The index displays statistically significant trends in Quetta (8 days increase), in Barkhan (16 days increase), in Dalbandin (18 days increase), and in Panjgur (10 days increase), all at 95 % level of confidence.
Observed indices of all Pakistan
Both mean maximum and mean minimum temperatures are increasing significantly by 0.8°C and o.9°C respectively over whole Pakistan (Figure 5.6). Summer days are shown to increase significantly by 15 days, while tropical nights are shown to increase significantly by 18 nights over whole Pakistan. Monthly minimum of daily maximum temperature has increased by 1.5°C, monthly minimum of daily minimum temperature has increased by 1.8°C, whereas, monthly maximum of daily minimum temperature has significantly decreased by 0.8°C. Frost days are decreasing significantly by 5 days in 54 years. Both cool days and cool nights are decreasing significantly by 7 days and 14 nights respectively over whole Pakistan. It is also seen that the cold spell duration index has decreased by 29 days over the 54 year period in whole Pakistan.
