The Penman-Monteith formulation of evaporation has been criticised for its reliance upon point estimates so that areal estimates of wetland evaporation based upon single weather stations may be misleading. Typically, wetlands comprise a complex mosaic of land cover types from each of which evaporative rates may differ. The need to account for wetland patches when monitoring hydrological fluxes ...

Quantification of precipitation extremes is important for flood planning purposes, and a common measure of extreme events is the r-year return-level. We present a method for producing maps of precipitation return levels and uncertainty measures and apply to a Colorado region. Separate hierarchical models are constructed for the intensity and the frequency of extreme precipitation events. For in...

On the premise that urban heat islands are strongest in calm conditions but are largely absent in windy weather, daily minimum and maximum air temperatures for the period 1950–2000 at a worldwide selection of land stations are analyzed separately for windy and calm conditions, and the global and regional trends are compared. The trends in temperature are almost unaffected by this subsampling, i...

In this paper, we propose a new hidden Markov model (HMM) for the space-time evolution of daily rainfall. The hidden Markov chain represents the different meteorological regimes (“weather types”) and it is assumed that this variable explains the dynamics of the precipitation. The spatial structure within hidden weather types is modelled by censored power-transformed Gaussian distributions. It p...

Wind gusts are parameterized in a numerical weather prediction model using a new method based on considerations of turbulence and atmospheric stability in the planetary boundary layer. This method was recently introduced by Brasseur and has already been successfully applied to various atmospheric situations, amongst those several in the complex terrain in Iceland. In this study, the method is a...

for the purposed water resources management, irrigation scheduling, water usage optimization and gaining maximum yield two step fao method was applied to determine the water requirement (evapotranspiration) of sugar beet.  in this paper reference evapotranspiration were computed from recorded meteorological data at 38 weather stations using the hargreaves-samani method; and then through applyin...

Water availability is the most important limiting factor in arid lands. Any additional source of water, such as dew and fog, may have a positive impact upon the ecosystem. Dew and fog precipitation are largely dictated by weather conditions and habitat. Dew and fog measurements were carried out for 29 days in the fall of 1987–1989 at three distinctive habitats within a single drainage basin in ...

iran is facing dust storms every year and frequently. this phenomenon has affected, especially in recent years, various aspects of people's lives. the aim of this research is iran’s seasonal clustering in terms of dust storms frequency with visibility less than 1000 and 500 m for the period of 1987–2008. for this purpose, we used the data of 87 synoptic stations that had suitable spatial d...

The South African Weather Service (SAWS) operates a nationwide network of ground-based meteorologic radar stations (National Weather Radar Network), providing data continuity in some regions dating back to 1994, which is unique for southern africa. The incoming data is processed and archived using the TITAN software package[1]. Thematic digital maps are derived which can be accessed through the...

Examining relationships in spatio-temporal data has lead to the construction of a decision support system specializing in data-mining. Several steps are taken with the system architecture to ensure a robust, easy to use online interface in a distributed environment, including the implementation of developing technologies and effective knowledge discovery algorithms. Drought risk management is t...