Gradual changes in temperature, humidity, rainfall, and solar irradiation as indicators of city climate change and increasing hydrometeorological disaster: a case study in Yogyakarta, Indonesia

Climate change began in the 1980s when global warming became a global concern, and it has continued in several cities in Indonesia. This paper measures climate change in Yogyakarta, Indonesia based on gradual changes in the air temperature, air humidity, rainfall depth, and duration of the sun's irradiation. The data were obtained for a period of 43 years (1976-2018) from the meteorological recording data at the climatology station in Yogyakarta. Data processing is done using the average statistical method, as outlined in the relationship graph between the years and the parameters studied. The results show that climate change in Yogyakarta has been clearly occurring. It is indicated by the increase of the average air temperature, the decrease of the average air humidity, the rising rainfall in the rainy season, and the changing of the sun's irradiation duration in the rainy season and in the dry season.