Climatic classification of Bangladesh

Using climatological data for 27 years of 16 stations an attempt has been made to classify the climate of Bangladesh by the method of Ivanov (1941. 1956 & 1958). Selianinov (1966). Gorsinkii and Shever (1976). By Ivanov's method it has been established that there are three climatic zones in Bangladesh (i) zone with simple humid climate- western bordering districts of Bangladesh; (ii) zone with sufficient humid climate -areas of Bangladesh mainly to the west of 90. E and (iii) zone with super humid climate areas or Bangladesh mainly to the east of 90"E. Almost analogous climatic zones have been obtained by Selianinov's method. By Gorsinkii's method. it has been shown that there are three climatic zones in Bangladesh' (i) quasi-maritime climate -southeastern and northeastern hilly areas; (ii} climate of the plain land- the central belt of the country. and (iii) quasi-continental clill1ate -western bordering districts. By Shevers method it has been shown that there is only sharp continental type of climate in Bangladesh.

Development of intensity based fog climatological information system (daily and hourly) at IGI airport, New Delhi for use in fog forecasting and aviation

The main objective of the present paper is to make a microclimatological study of occurrence of fog of different intensities at Indira Gandhi International (IGI) airport, New Delhi which includes their date-wise climatological probabilities and their corresponding total number of hours of occurrence for 62-days of peak winter from 1st December to 31st January by using hourly visibility data for the period of 1981-2005. Their hourly climatology has been discussed separately for both months using same data for understanding their diurnal variations. Both the computations have been done to find most vulnerable periods with exact dates and timings when both duration and intensity of the fog are very high and hazardous for aviation. Corresponding 10-days and 3-hourly climatology of cumulative fog occurrences are computed to identify a period when fog related flight diversion risk is highest. For better understanding of their variability, dates of extreme hours of occurrences of a particular fog type amongst occurrences of all dates for the period during both months have also been documented. These climatological informations can be used by various airlines for planning flight operation and action for establishment of fog dissipation mechanism. Finally, fogprobability matrices of various intensities based on these climatological data have been presented with dates in first column and hours in the first row for all 62 days of December and January and for all 24 hours of each day giving date and hour wise climatological probability of their occurrences which can be used at IGI as climatological tool for forecasting of fog of various intensity and expected climatological period.

Latitudinal distribution of water vapour over the Arabian Sea and Bay of Bengal using Bhaskara-II SAMIR data

The main purpose of the present work is to establish the reliability of the SAMIR-derived water vapour (WV) data over the Arabian Sea and the Bay of Bengal for the entire 18-month from January 1982 to June 1983 period of the in-orbit operation of the SAMIR system. The average latitudinal distributions of WV over the Arabian Sea and Bay of Bengal for different months, derived from the SAMJR data were found to be broadly consistent with the climatological data on WV from the coastal and island radiosonde stations. A significant latitudinal gradient in WV has been found during the northern winter months (Dec-Feb) with the highest value of 4-5 gm/cm2 near the equator and thc lowest value of about 2 gm/cm2 at about 20oN over the Indian seas. This gradient gradually decreases during the subsequent months and almost vanishes during the southwest monsoon months (Jun-Sep) when the WV has nearly uniform value of 4-5 gm/cm2 in the entire latitude range from the equator to 20oN over the Indian seas. Finally, it has been found that WV values over the Bay of Bengal are generally higher than those over the Arabian Sea at co-latitudinal positions. The implications of this result are discussed in the light of other considerations.

Some climatological characteristics of mean sea level pressure in Bangladesh

On the basis of climatological data of 30 years (1951-1980) for 16 stations a climatological study of mean sea level pressure in Bangladesh has been accomplished. Spatial distribution and actual variation of mean sea level pressure have been studied. Attempt has been made to explain the cause of annual variation of mean sea, level pressure in Bangladesh from the point of view of synoptic meteorology. "Stability" of the meteorological stations of Bangladesh with respect to mean sea level pressure has been quired. The spatial variations of correlation of coefficients with regard to mean sea level pressure have been analysed. Finally, some characteristics of probabilities of mean sea level pressure at different materials for selected stations have been obtained.

An investigation of monthly mean maximum and absolute maximum temperatures of Bangladesh

Using synoptic and climatological data for 27 years (1951-1977) of 16 stations of Bangladesh, temporal and spatial variations of the ab3olute maximum temperature of Bangladesh have been studied. Empirical probabilities for the interval 35.loC-40.o0C and 40,1° -45.0°C of absolute maximum temperature have been examined. Some correlation characteristics between some pairs of station for some selected months have been analysed. An attempt has been made to explain the cause of temporal and spatial variations of maximum and absolute maximum temperatures from the point of view of synoptic meteorology.

Kalibrasi Model Soil Moisture Accounting dengan Software HEC-HMS di Stasiun Debit Pasir Pangaraian

This research aims to compare the results of the calibration of the Soil Moisture Accounting (SMA) model using Percent Error in Volume (PEV) and Peak Weighted Root Mean Square Error (RMSE). The SMA model calibration uses the HEC-HMS (Hydrologic Engineering Center – Hydrologic Modeling System). There are 12 calibrated parameters by automatic calibration. The input data are the area of ​​the watershed, daily rainfall, daily discharge data and climatological data. The data used is data from 2008 to 2017. The results show that PEV performance shows good results. While the RMSE showed poor results. PEV results are best at 7 years of calibration and 3 years of verification. The length of the calibration data has not affected the verification results.

Some climatological characteristics of relative humidity in Bangladesh

Using climatological data for 30 years (1951-1980) for twelve stations. some characteristics of relative humidity (RH) in Bangladesh have been studied. In doing so, annual variation, spatial distribution, diurnal and annual amplitudes of RH have been investigated. The correlation characteristics of RH between Dhaka and some other stations have been analysed. Finally, the date of beginning and ending and the duration of RH in some defined limits (above 75%, 80% and 85%) have been discussed: An attempt has also been made to explain the cause of temporal and spatial variations from synoptic point of view.

Sub-seasonal variations of the tropical storm track in the western north Pacific

With 20-year (1975-94) climatological data, we demonstrate that the tropical storm track over the western North Pacific (0° - 40°N, 100 - 180°E) exhibits prominent sub-seasonal variations on a time scale of about 40 days from May to November. The storm track variability is regulated by the conspicuous Climatological Intra Seasonal Oscillation (CISO) in the strength of the western North Pacific summer monsoon and the associated position of the western Pacific Sub-tropical High. The CISO cycle regulates the number of tropical storm formation during the Pre-Onset and Withdraw Cycles but not during the Onset and Peak Monsoon Cycles (from mid-June to mid-September).

Identification of Suitable Sites for Jatropha curcas L. Bioenergy Plantation Using the AquaCrop Model

Jatropha curcas (JC), as a biofuel plant, has been reported to have various desired characteristics such as high oil content seeds (27–40%), fast-growth, easy cultivation, drought tolerance, and can be grown on marginal soil and wasteland, requiring fewer nutrients and management and does not interfere with existing food crops, insects, and pest resistance. This investigation was the first study of its type to use climatological data, blue/green water footprints, and JC seed production to identify suitable sites for JC bioenergy plantation using the AquaCrop FAO model across the Khyber Pakhtunkhwa province in northwest Pakistan. The JC seed yield (10 ton/ha) was at a maximum in the districts of Bannu, Karak, Hangu, Kurram, North Waziristan, Lakki Marwat, South Waziristan, and Dera Ismail Khan, in addition to its frontier regions, Tank, Peshawar, Mohmand, Orakzai, Khyber, Kohat, Charsadda, Mardan, Swabi, and Nowshera, respectively. Green water footprint (264 m3/ton of JC seed) and blue water footprint (825 m3/ton) was less in these areas. Furthermore, the results revealed that, depending on climatological circumstances, the southern part of the Khyber Pakhtunkhwa province is more appropriate for JC bioenergy plantation than the northern region. The districts of Bannu, Karak, Hangu, Kurram, North Waziristan, Lakki Marwat, South Waziristan, Dera Ismail Khan, and its frontier regions, Tank, Peshawar, Mohmand, Orakzai, Khyber, and Kohat, in Khyber Pakhtunkhwa province were identified to be the most ideal places for JC bioenergy plantation. As a result, under the Billion Tree Afforestation Project (BTAP) and the Green Pakistan Project, the Forest Department of Khyber Pakhtunkhwa should consider planting JC species in the province’s southern region. Furthermore, this research will provide scientific information to government and private sector officials for better management and optimum yield of the JC biofuel crop, as well as for the promotion of energy forestry in Pakistan.

Some climatological characteristics of the changing pattern of temperature in Bangladesh – A diagnostic approach

Based on climatological data of maximum and minimum temperatures of seventeen stations for a period of 60 years (1949 - 2008), obtained from Bangladesh Meteorological Department (BMD), the changing pattern of temperature in Bangladesh has been investigated. Some characteristics of annual variation and spatial distribution of mean monthly minimum, mean monthly maximum and mean monthly temperature, annual variation and spatial distribution of mean monthly amplitude of temperature have been explained. The characteristics of changing pattern of temperature such as standard deviation, coefficient of variation, ratio between mean monthly maximum and mean monthly minimum temperatures have been studied. The run of the temperature in different stations for the years 1949-2008, the periodicity of mean annual temperature and mean decade deviations have been discussed. The integral curve of mean annual temperature for Dhaka has been prepared and explained. Regression analysis for mean monthly temperature of January, April, July and October for the stations Sylhet, Chittagong, Khulna and Rangpur with Dhaka have been analyzed. Some linear correlation equations have been deduced. In the investigation, attempts (as far as possible) have been made to explain the synoptic cause of the changing pattern of temperature in Bangladesh.