SOLAR ENERGY POTENTIAL FORECAST IS A PIVOTAL INFORMATION NEEDED IN THE OPERATIONAL ACTIVITY OF LARGE-SCALE SOLAR ENERGY PRODUCTION. IN THIS STUDY, THE RELIABILITY OF SSRD (SURFACE SOLAR RADIATION DOWNARD) FORECAST FROM THE 51 ENSEMBLE MEMBERS IN THE ECMWF (EUROPEAN CENTRE FOR MEDIUM RANGE FORECAST) LONG-RANGE FORECAST TO PREDICT DAILY AND MONTHLY SOLAR ENERGY POTENTIAL IN 15 STATIONS IN INDONESIA IS EVALUATED. THE GLOBAL HORIZONTAL IRRADIANCE (GHI) DATA FROM THE ASRS (AUTOMATIC SOLAR RADIATION STATION) OBSERVATION NETWORK FROM JANUARY 2019 – JUNE 2020 ARE USED IN THE QUANTITATIVE VERIFICATION OF THE SSRD FORECAST. POST-PROCESSING METHODS ARE APPLIED TO THE MODEL OUTPUT, NAMELY THE BILINEAR INTERPOLATION METHOD AND THE EMPIRICAL QUANTILE MAPPING TO REDUCE CONSISTENT BIASES IN THE MODEL OUTPUT. THE EVALUATION WAS CARRIED OUT FOR DIFFERENT CLOUD COVERS BASED ON THE CALCULATION OF CLEARNESS INDEX (KT). THE RESULTS SHOW THAT THERE IS A BETTER ASSOCIATION BETWEEN MODELLED AND OBSERVED SOLAR RADIATION IN THE DRY SEASON COMPARED TO THE RAINY SEASON IN MOST LOCATIONS. HIGHER CORELATIONS AND LOWER BIASES ARE FOUND IN HIGHER LATITUDES STATIONS COMPARED TO STATIONS IN THE EQUATORIAL REGION. SIGNIFICANT IMPROVEMENTS WERE OBTAINED AFTER THE STATISTICAL POST-PROCESSING, INDICATING THE FEASIBILITY OF THE FORECASTS TO BE USED IN THE INDONESIA REGION.

TO PROVIDE WEATHER AND CLIMATE-RELATED SERVICES FOR DISASTER MANAGEMENT, PUBLIC POLICYMAKING, AND ADAPTATION AND MITIGATION EFFORTS, THE INFORMATION REGARDING CLIMATE CHANGE IS OF HIGH IMPORTANCE. HOWEVER, OBTAINING OR ANALYZING CLIMATE CHANGE DATASETS HAS BEEN A CHALLENGE FOR THOSE WHO ARE NOT FAMILIAR WITH CODING. THEREFORE, TO MAKE THE DATASETS EASIER TO OBTAIN AND WORK WITH, WE DEVELOP A TOOL CALLED “SOUTHEAST ASIA – CLIMATE-OCEAN WEB APP” (SEA-COAPP). THE SEA-COAPP IS A WEB APP TO AID PEOPLE TO OBTAIN, ANALYZE, OR VISUALIZE ROM DATASETS IN SOUTHEAST ASIA. IT CAN BE USED TO OBTAIN CHUNKS OF DATA FROM THE INAROMS SERVER AND VISUALIZE IT EASILY WITH AN INTUITIVE GRAPHICAL USER INTERFACE. FURTHERMORE, IT ALSO HAS FUNCTIONALITIES TO CALCULATE CLIMATOLOGY, AREA-AVERAGE, ANOMALY, AND TRENDS. THE TOOL CAN HELP THOSE WHO ARE UNFAMILIAR WITH CLIMATE CHANGE DATASETS TO BE ABLE TO USE THE DATASETS FOR THEIR RESEARCH. THUS, PROMOTING CROSS-DISCIPLINARY RESEARCH.

VEGETATION COVER CHANGES ARE IMPORTANT INFORMATION IN FOREST AND PLANTATION AREAS, THESE CHANGES CONSIST OF DEVEGETATION AND REVEGETATION INFORMATION. THIS INFORMATION CAN BE IDENTIFIED THROUGH THE LANDSAT-8 DATA MOSAIC. THE RESEARCH OBJECTIVE WAS TO DETERMINE THE THRESHOLD FOR DEVEGETATION AND REVEGETATION, SO THAT THE VEGETATION COVER CHANGE CAN BE IDENTIFIED QUICKLY. THE STUDY LOCATIONS ARE SUMATRA, JAVA, AND KALIMANTAN WITH ZONE A AND B CLIMATES OF THE OLDEMAN TYPE, WHICH COVER THE LARGEST AREA AND THE CHANGES ARE VERY DYNAMIC IN INDONESIA. THE METHOD USED THE REGIONS OF INTEREST TAKEN IN SUMATRA THROUGH ITS NBR VALUE TO DETERMINE THE THRESHOLD. OBTAINED THRESHOLD VALUE ARE 197 FOR REVEGETATION AND 207 FOR DEVEGETATION ON A SCALE OF 256. THE THRESHOLD VALUE IS  APPLIED IN JAVA AND KALIMANTAN IN THE SAME CLIMATE ZONE. THE RESULT IS VISUALLY, IT CAN BE SEEN THAT VEGETATION COVER CHANGES  IN JAVA AND KALIMANTAN IN ZONE A AND B TYPES OF OLDEMAN CLIMATE CAN BE IDENTIFIED PROPERLY.

WATER BALANCE IS USED TO DETERMINE HYDROLOGICAL CONDITIONS IN A WATERSHED BY ANALYZING THE NUMBER OF MONTHS OF SURPLUS AND DEFICIT THAT OCCURRED, WHICH IN EXTREME CONDITIONS CAN CAUSE HYDROMETEOROLOGICAL DISASTERS, SUCH AS FLOODS OR DROUGHTS. THIS STUDY AIMS TO CALCULATE THE WATER BALANCE USING THE THORNTHWAITE-MATHER METHOD. THE DATA USED ARE MONTHLY HYDROMETEOROLOGICAL DATA FOR 2010-2019 (10 YEARS) WHICH ARE DIVIDED INTO 2 WATER BALANCE PERIODS BASED ON LAND USE, 2011 FOR THE 2010-2014 PERIOD AND 2016 FOR THE 2015-2019 PERIOD, IN THE BENGKULU WATERSHED WHICH IS DIVIDED INTO 3 SUB-WATERSHEDS, NAMELY RINDU HATI, SUSUP, AND BENGKULU HILIR. THE CALCULATION RESULTS SHOW THAT THE RINDU HATI AND SUSUP SUB-WATERSHEDS HAVE THE SAME WATER BALANCE CONDITION, NAMELY THE DEFICIT WITH THE HIGHEST NUMBER OF EVENTS OCCURRED FOR 5 MONTHS IN 2015 AND 2019, WHILE IN THE BENGKULU HILIR SUB-WATERSHED, THE DEFICIT OCCURRED ALMOST EVERY YEAR AND THE HIGHEST NUMBER OF EVENTS OCCURRED FOR 7 MONTHS IN 2019. OVERALL, THE DEFICIT WITH THE HIGHEST NUMBER OF EVENTS OCCURRED IN SEPTEMBER.

KEYWORDS: HYDROMETEOROLOGY, WATER BALANCE, THORNTHWAITE-MATHER, HYDROLOGY, BENGKULU

 

THERE IS UNIQUENESS IN CLIMATE SERVICES IN EAST JAVA. RAINFALL INFORMATION ARE DELIVERED AS N-1 ANALYSIS FOR ONGOING MONTH , N+1, N+2, AND N+3 FOR MONTHLY PREDICTION. THIS STUDY AIMS TO INVESTIGATE WETHER UPDATING MONTHLY PREDICTION IMPROVES PREDICTION ACCURACY. THE VERIFICATION METHOD FOR THIS STUDY IS BASED ON THE PERCENTAGE ACCURACY OF RAIN CLASS CATEGORY ACCORDING TO SNI 8196: 2015. THE DATA USED FOR THIS STUDY IS ECMWF’S MONTHLY RAINFALL PREDICTION THAT HAS THREE LAGS SYSTEM (1,2, AND 3). RASTERS OF MONTHLY RAINFALL INTERPOLATION FROM THE MAIN RAINFALL OBSERVATION (197 LOCATIONS) IN EAST JAVA FROM APRIL 2015 TO MAY 2020 (62 MONTHS) ARE USED FOR VERIFICATION PROCESS. THE TEMPORAL AND SPATIAL ANALYSIS THEN CONDUCTED USING R (+ PACKAGE RASTER). ANALYSES BASED ON LOCAL GOVERMENTAL ZONE ARE ALSO USED. IN GENERAL, THE RESULT SHOWS THAT FOR NOVEMBER, DECEMBER, JANUARY, FEBRUARY, MARCH, JUNE, AND SEPTEMBER (NDJFM AND JS) NEEDS MONTHLY UPDATING. VERIFICATION OF ECMWFS4 SHOWS A BETTER VERIFICATION RESULT (0,56) IN THE PAST FIVE YEARS (2016-2020) FOR MARCH. THE REGIONS THAT NEED MONTHLY UPDATING ARE BAWEAN ISLAND, THE COAST OF GRESIK, PASURUAN, AND BANYUWANGI.

 

KEYWORDS: UPDATING, MONTHLY RAINFALL, VERIFICATION, ECMWF 

REVISED VERSION

 

CLIMATE CHANGE HAS A SIGNIFICANT INFLUENCE ON WEATHER CONDITIONS, ESPECIALLY RAINFALL, WHICH DIRECTLY IMPACTS WATER AVAILABILITY IN AN AREA. THE BALI REGION AS ONE OF THE INTERNATIONAL TOURISM DESTINATION IS EXPERIENCING A SURFACE WATER CRISIS WHERE THE SURFACE WATER AVAILABILITY (LAKES OR RIVERS) IS NOT ABLE TO KEEP UP WITH THE ESCALATING IN WATER DEMAND DUE TO THE INCREASING POPULATION, TOURIST ATTRACTIONS AND EXPANSION OF TRANSPORTATION FACILITIES. I GUSTI NGURAH RAI AIRPORT, LIKE MOST URBAN AREAS IN BALI IN GENERAL, RELIES DOMINANTLY ON UNDERGROUND WATER TO FULFIL ITS WATER DEMAND. ALTHOUGH GROUNDWATER SYSTEMS ARE GENERALLY MORE RESILIENT TO CLIMATE CHANGE THAN SURFACE WATER SOURCES, THEIR OVERUSE MIGHT CAUSE LOWERING OF THE WATER TABLE, REDUCTION OF WATER IN STREAMS AND LAKES, LAND SUBSIDENCE AND DETERIORATION OF WATER QUALITY. ONE ALTERNATIVE TO OVERCOME THIS PROBLEM IS RAINWATER HARVESTING (RWH) WHICH CAN BE IMPLEMENTED IN AN AREA TO INCREASE THE AVAILABILITY OF RAW WATER AND REDUCE FLOOD INUNDATION. HOWEVER, IN INDONESIA, THE STUDY OF THE POTENTIAL OF RWH AT A REGIONAL SCALE IS STILL LIMITED, SO IT DOES NOT PROVIDE SUFFICIENT INFORMATION FOR PRACTICAL APPLICATION. THEREFORE, IT IS NECESSARY TO CONDUCT A STUDY ON THE POTENTIAL FOR HARVESTING RAINWATER AT I GUSTI NGURAH RAI AIRPORT TO MEET THE DEMAND FOR WATER IN THIS REGION BOTH IN THE RAINY OR LA NINA SEASON WHICH HAS A LOT OF RAINFALL AND IN THE DRY OR EL NINO SEASON WITH LOW RAINFALL. TO ACHIEVE THOSE PURPOSES, THIS STUDY INTENDS TO OBTAIN AN RWH STORAGE CURVE SO THAT IT CAN BE A PRACTICAL REFERENCE FOR USERS IN CHOOSING THE STORAGE VOLUME ACCORDING TO THE CATCHMENT AREA, THE AMOUNT OF WATER NEEDED AND THE DESIRED RELIABILITY. FURTHERMORE, THE RECALCULATION OF HIGH AND LOW RAINFALL PERIODS IS CONTRIBUTED NOT ONLY TO DETERMINE THE STEPS FOR MITIGATING THE WATER CRISIS AT I GUSTI NGURAH RAI AIRPORT BUT ALSO TO PERFORM OTHER FUNCTIONS SUCH AS THE MUCH-NEEDED GREENING OF DENSE AREAS IN THE AIRPORT AREA. LASTLY, THIS STUDY WILL UTILIZE A SIMULATION ANALYSIS METHOD TO CALCULATE THE STORAGE VOLUME WITH RAINFALL, VARIATIONS IN THE CATCHMENT AREA, WATER REQUIREMENTS AND RELIABILITY LEVELS. AS A RESULT, THIS WILL BE USED TO DETERMINE WHETHER THE VOLUME OF RAINFALL AT I GUSTI NGURAH RAI AIRPORT HAS THE POTENTIAL TO MEET WATER NEEDS IN EACH SEASON (DRY, RAINY AND TRANSITIONAL). 

KEYWORD: WATER PROBLEM, RAINWATER, HARVESTING, MITIGATING

 

 

SUFFICIENT WATER AVAILABILITY DURING THE VEGETATIVE, REPRODUCTIVE AND EARLY RIPENING PHASES OF RICE PLANT IS VERY IMPORTANT. INFORMATION ON DROUGHT SUCH AS CONSECUTIVE DRY DAYS (CDD) PREDICTIONS IN THIS PERIOD BECAME VERY CRUCIAL AND HAVE IMPORTANT ROLE TO MAINTAIN RICE PRODUCTION STABILITY. THE AIM OF THIS STUDY IS TO INVESTIGATE PERFORMANCE OF CDD MULTI MODEL ENSEMBLE PREDICTION, WHICH APPLIED ON SOUTH SULAWESI RICE PRODUCTION CENTERS. CDD OBSERVATION WAS CALCULATED USING HIGH RESOLUTION GRIDDED PRECIPITATION BLENDING DATA, OBTAINED FROM BMKG PRECIPITATION NETWORK STATIONS AND THE DAILY-IMPROVED CLIMATE HAZARDS GROUP INFRARED PRECIPITATION WITH STATIONS (CHIRPS) VERSION 2.0. THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) MONTHLY PRECIPITATION HINDCAST DATA DURING 1982 – 2010 PERIODS FROM EACH 9 INDIVIDUAL GLOBAL CLIMATE MODELS WERE USED TO DEVELOP SEASONAL CDD PREDICTIONS. WORLD METEOROLOGICAL ORGANIZATION (WMO) STANDARD VERIFICATION FOR LONG RANGE FORECAST (SVS-LRF) METHOD APPLIED TO DESCRIBE THIS CDD PREDICTION PERFORMANCE ON FOUR DIFFERENT SEASONS. INVESTIGATION OF MODEL PERFORMANCE DURING STRONG EL NIÑO EVENT IN 1997 ALSO CONDUCTED IN ORDER TO GET GENERAL SKILL OVERVIEW REGARDING EXTREME CLIMATE EVENT. BEST PERFORMANCE OF CDD PREDICTION GENERALLY OCCURRED DURING JJA AND DJF PERIOD. MME CDD PREDICTION SHOWS BETTER PERFORMANCE COMPARED TO INDIVIDUAL MODEL PERFORMANCE FOR ALMOST ALL SEASON. SPATIAL COHERENCE BETWEEN PREDICTION AND OBSERVATION OVER RICE PRODUCTION CENTERS DURING 1997 EL NIÑO CONFIRMS THE SKILL OF CDD PREDICTIONS. THE APPLICATION OF THIS PREDICTION ON AGRICULTURAL SECTOR WILL BE VERY USEFUL IN ORDER TO SUPPORT RICE PRODUCTION SUSTAINABILITY AND FOOD SECURITY. FURTHER ANALYSIS RESULT CAN BE FOUND ON FULL PAPER.

KEYWORDS : CDD PREDICTION, WMO SVS-LRF, RICE PRODUCTION CENTER, MULTI MODEL ENSEMBLE, CLIMATE MODELS