Precipitation

About: Precipitation is a research topic. Over the lifetime, 32861 publications have been published within this topic receiving 990496 citations. The topic is also known as: rain & rainfall.

Projections of extreme precipitation events in regional climate simulations for Europe and the Alpine Region

Abstract: [1] Regional climate models (RCMs) from the ENSEMBLES project are analyzed to assess projected changes in 21st century heavy and extreme precipitation events over Europe. A set of 10 RCMs with horizontal grid spacing of 25 km is considered, which are driven by six GCMs under an A1B greenhouse gas scenario. The diagnostics include basic precipitation indices (including mean, wet-day frequency, intensity, and percentile exceedance) and application of generalized extreme value theory for return periods up to 100 years. Changes in precipitation climate between present (1970–1999) and future (2070–2099) conditions are presented on a European scale and in more detail for 11 European regions (mostly in supplemental figures). On the European scale, projections show increases (decreases) in mean amounts and wet-day frequency in northern (southern) Europe. This pattern is oscillating with the seasonal cycle. Changes in extremes exhibit a similar pattern, but increases in heavy events reach much further south. For instance, during spring and fall, much of the Mediterranean is projected to experience decreases in mean precipitation but increases in heavy events. Thus, projected changes in mean and extremes may show different signals. The inter-model spread is partly attributable to a GCM-dependent clustering of the climate change signal, but also affected by RCM uncertainties, in particular in summer. Despite these uncertainties, many of the projected changes are statistically significant and consistent across models. For instance, for the Alps, all models project an intensification of heavy events during fall, and these changes are statistically significant for a majority of the models considered.

A daily soil temperature model based on air temperature and precipitation for continental applications

Abstract: Soil temperature is a necessary component for estimating below-ground processes for continental and global carbon budgets; however, there are an insufficient number of climatic stations monitoring soil temperature. We used a n 11-day running average of daily mean air temperature to estimate daily mean soil temperature at a depth of 10 cm using linear regression. This model was tested using data from 6 climate reg~ons across the United States. Frequency analyses for 17 of 19 data sets showed that the number of days which were w~thin a k3.5OC range centered on the measured sol1 temperature va r~ed from 77 to 96%. The values of R2 between observed and final predicted soil temperatures ranged from 0.85 to 0.96 with standard errors from 1.5 to 2.9"C for all 19 simulations. Changes of soil temperature under snow cover were smaller than those without snow cover. Soil temperature under vegetation cover was also simulated assuming the rate of soil warming under vegetation cover would be reduced with increasing leaf area index according to the Beer-Lambert Law. Annual soil respiration can be estimated from the predicted soil temperature with reasonable accuracy. Daily soil temperature may be predicted from daily air temperature once regional equations have been established, because weather stations in the United States can be generalized into a few regions and sites wthin each region may use the same equation.

The Structure and Evolution of Convection in a Tropical Cloud Cluster

Abstract: A large cloud cluster which occurred over the data network of the Global Atmospheric Research Program's Atlantic Tropical Experiment (GATE) on 5 September 1974 is examined. Data from four quantitative shipboard weather radars show that virtually all of the precipitation in the tropical cloud cluster was associated with six mesoscale precipitation features. A prototype for the structure and life cycle of these features is presented which is sufficiently general to describe all six precipitation features, one of which was a tropical squall-line system. These mesoscale features appear to he the primary entitles within which deep tropical convection occurs. In their formative stage, mesoscale precipitation features consist of a line of isolated cumulonimbus cells oriented perpendicular to the low-level wind flow. In the intensifying stage, the rain areas of the individual cells merge when new convective cells develop between and ahead of the existing cells, where the outflow from convective-scale dow...

Meteorological Causes of the Secular Variations in Observed Extreme Precipitation Events for the Conterminous United States

Abstract: Daily extreme precipitation events, exceeding a threshold for a 1-in-5-yr occurrence, were identified from a network of 935 Cooperative Observer stations for the period of 1908–2009. Each event was assigned a meteorological cause, categorized as extratropical cyclone near a front (FRT), extratropical cyclone near center of low (ETC), tropical cyclone (TC), mesoscale convective system (MCS), air mass (isolated) convection (AMC), North American monsoon (NAM), and upslope flow (USF). The percentage of events ascribed to each cause were 54% for FRT, 24% for ETC, 13% for TC, 5% for MCS, 3% for NAM, 1% for AMC, and 0.1% for USF. On a national scale, there are upward trends in events associated with fronts and tropical cyclones, but no trends for other meteorological causes. On a regional scale, statistically significant upward trends in the frontal category are found in five of the nine regions. For ETCs, there are statistically significant upward trends in the Northeast and east north central. For the ...

Suppression of south Asian summer monsoon precipitation in the 21st century

Abstract: [1] We used a high-resolution nested climate modeling system to investigate the response of South Asian summer monsoon dynamics to anthropogenic increases in greenhouse gas concentrations. The simulated dynamical features of the summer monsoon compared well with reanalysis data and observations. Further, we found that enhanced greenhouse forcing resulted in overall suppression of summer precipitation, a delay in monsoon onset, and an increase in the occurrence of monsoon break periods. Weakening of the large-scale monsoon flow and suppression of the dominant intraseasonal oscillatory modes were instrumental in the overall weakening of the South Asian summer monsoon. Such changes in monsoon dynamics could have substantial impacts by decreasing summer precipitation in key areas of South Asia.