Precipitation trend analysis, on different spatial and temporal scales, has been of great concern during the past century because of the attention given to global climate change by the scientific community. According to some recent studies, the Italian territory has been suffering a precipitation decrease, especially in the last 50 years, and the southern areas seem to be more affected. The aim of the present study is to analyse rainfall time series over a wide time interval and a wide area, detecting potential trends and assessing their significance. For this purpose, 211 gauged stations, mainly located within the Campania region, southern Italy, have been analysed for the period 1918–1999. An accurate database has been set up through a data quality and time series homogeneity process. Statistical analysis of the database highlight that (1) the trend appears predominantly negative, both at the annual and seasonal scale, except for the summer period when it appears to be positive; (2) over the whole reference period, positive and negative trends are significant respectively for 9 and 27% of total stations and (3) over the last 30 years, a negative trend is instead significant for 97% of the total stations. Copyright © 2009 Royal Meteorological Society

Water use efficiency in agriculture can be improved by implementing advisory systems that support on-farm irrigation scheduling, with reliable forecasts of the actual crop water requirements, where crop evapotranspiration (ET_c) is the main component. The development of such advisory systems is highly dependent upon the availability of timely updated crop canopy parameters and weather forecasts several days in advance, at low operational costs. This study presents a methodology for forecasting ET_c, based on crop parameters retrieved from multispectral images, data from ground weather sensors, and air temperature forecasts. Crop multispectral images are freely provided by recent satellite missions, with high spatial and temporal resolutions. Meteorological services broadcast air temperature forecasts with lead times of several days, at no subscription costs, and with high accuracy. The performance of the proposed methodology was applied at 18 sites of the Campania region in Italy, by exploiting the data of intensive field campaigns in the years 2014–2015. ET_c measurements were forecast with a median bias of 0.2 mm, and a median root mean square error (RMSE) of 0.75 mm at the first day of forecast. At the 5^th day of accumulated forecast, the median bias and RMSE become 1 mm and 2.75 mm, respectively. The forecast performances were proved to be as accurate and as precise as those provided with a complete set of forecasted weather variables.