Local Climate Variability Associated to Sustainable Agriculture at Rain Shadow Areas of the Mount Rinjani and Tambora in West Nusa Tanggara Mahrup , AB Baharuddin, Mulyati, LE Susilowati, Padusung and Fahrudin
Dept. of Soil Science, Agriculture Faculty, Mataram University
Abstract
Abstract. Local climate variability is driven by solar energy received on the earth surface and about 30 percent reflected back to the atmosphere. Climate variables affected by the solar energy are, temperature, atmospheric pressure, relative humidity, wind and rain which are all associated to agriculture. In addition, mountains play a significant role in affecting local climate and inducing rain shadow areas which are typical of dry land agriculture. A descriptive research was conducted to study variability of local climate variability associated to direct normal solar irradiation (DNI), and its possible impact on sustainable agriculture at rain shadow areas of Mt. Rinjani in Lombok and Tambora in Sumbawa, West Nusa Tenggara. The results show that the intensity of DNI was relative similar at both sides of the Mt. Rinjani where there was 13.2 MJ/m2 day at northern side, and 13.1MJ.m-2 day at southern side. While at Mt. Tambora, there was 13.6 MJ/m2 day at northern side, and 15.6 MJ/m2day at southern side. The DNI was relatively high in low lands, 16.6 MJ/m2 day and 17.3 MJ/m2 day for Lombok and Sumbawa respectively. At medium lands it was 12.4 MJ/m2 day and 13.9MJ/m2 day for Lombok and Sumbawa respectively. At high lands it was 10.4 MJ/m2 day for Lombok and 12.4 MJ/m2 day for Sumbawa. ETo, air and soil surface temperature were relatively high at rain shadow areas located at northern side of the Mt. Rinjani, and at the southern side of Mt. Tambora. In conclusion, the intensity of DNI was not significantly affected by aspect factor of incoming light relative to the both mountains. The Mountains had affected the variability of local climate depending on direction of wind bearing water vapor heading to the mountains. Rain shadow areas had been performed to the north from Mt Rinjani and to the south from Mt. Tambora.
