introduction drought is a climatic hazard that occurs in the vast areas throughout the world. it causes physical suffering, economic losses, and environmental instability. drought is a slowly developing very which is phenomenon, and it is very difficult to determine when a dry spell becomes a drought or when a severe drought becomes an exceptional drought. it is usually starting with less drama...

Decadal and centennial mean state changes in South American summer monsoon (SASM) precipitation during the last 2,300 years are detailed using an annually resolved authigenic calcite record of precipitation δ(18)O from a varved lake in the Central Peruvian Andes. This unique sediment record shows that δ(18)O peaked during the Medieval Climate Anomaly (MCA) from A.D. 900 to 1100, providing evide...

The potential impact of Indian Ocean sea surface temperature (SST) anomalies in modulating mid-latitude precipitation across southern and western regions of Australia is assessed in a series of atmospheric general circulation model (AGCM) simulations. Two sets of AGCM integrations forced with a seasonally evolving characteristic dipole pattern in Indian Ocean SST consistent with observed “dry-y...

drought is one of the most important weather-induced phenomena which may have severe impacts on different areas such as agriculture, economy, energy production, and society. a number of drought indices have been introduced and used in various countries to date. in the current study, four meteorological drought indices including percent of normal precipitation index (pnpi), standard index of ann...

Precipitation over the contiguous United States exhibits large multi-decadal oscillations since the early twentieth century, and they often lead to dry (e.g., 1946–1976 and 1999-present) and wet (e.g., 1977–1998) periods and apparent precipitation trends (e.g., from the 1950s to 1990s) over most of the western and central US. The exact cause of these inter-decadal variations is not fully unders...

Atmospheric circulation indices can be used to explain the variability of runoff on a continental scale. Beside well-known regional anomalies of precipitation and runoff that correlate with phases of the North Atlantic Oscillation (NAO) there are also drifting fields of annual discharge anomalies. Following the trend of the NAO, these fields move along a longitudinal axis from western Europe to...

Precipitation of γ’ phase in nickel-base superalloy IN792-5A was studied using in-situ Small Angle Neutron Scattering (SANS). It was found that additional precipitates are formed after reheating above 600 ̋C when the material is previously fast cooled (100 K/min) from 900 ̋C. The size distribution and volume fraction of the additional γ’ precipitates as well as of the already present medium-siz...