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.

Diurnal Variability of the Hydrologic Cycle in a General Circulation Model

Abstract: In the present Colorado State University GCM simulation-based analysis of the diurnal and semidiurnal variability of precipitation, precipitable water, evaporation, cloudiness, horizontal moisture flux convergence, and cloud radiative forcing, a realistic afternoon precipitation maximum is obtained over land in warm rainy regions, as well as an early morning maximum over the oceans. The model has been further used to investigate the bases for the oceanic diurnal-precipitation cycle; the results thus obtained indicate that such an oceanic cycle occurs even in the absence of neighboring continents, and tends to have a morning maximum, although the observed phenomenon is generally stronger than the results indicate.

Unexpected impacts of climate change on alpine vegetation

Abstract: The vegetation in a high alpine site of the European Alps experienced changes in area between 1953 and 2003 as a result of climate change. Shrubs showed rapid expansion rates of 5.6% per decade at altitudes between 2400 m and 2500 m. Above 2500 m, vegetation coverage exhibited unexpected patterns of regression associated with increased precipitation and permafrost degradation. As these changes follow a sharp increase in both summer and annual temperatures after 1980, we suggest that vegetation of the alpine (2400–2800 m) and nival (above 2800 m) belts respond in a fast and flexible way, contradicting previous hypotheses that alpine and nival species appear to have a natural inertia and are able to tolerate an increase of 1–2°C in mean air temperature.

Extreme snowfall events linked to atmospheric rivers and surface air temperature via satellite measurements

Abstract: [1] Narrow bands of strong atmospheric water vapor transport, referred to as “atmospheric rivers” (ARs), are responsible for the majority of wintertime extreme precipitation events with important contributions to the seasonal water balance We investigate relationships between snow water equivalent (SWE), precipitation, and surface air temperature (SAT) across the Sierra Nevada for 45 wintertime AR events Analysis of assimilated and in situ data for water years 2004–2010 indicates that ARs on average generate ∼4 times daily SWE accumulation of non-AR storms In addition, AR events contributed ∼30–40% of total seasonal SWE accumulation in most years, with the contribution dominated by just 1–2 extreme events in some cases In situ and remotely sensed observations show that SWE changes associated with ARs are closely related to SAT These results reveal the previously unexplored significance of ARs with regard to the snowpack and associated sensitivities of AR precipitation to SAT

Impact of Land-Surface Moisture Variability on Local Shallow Convective Cumulus and Precipitation in Large-Scale Models

Abstract: Numerical experiments using state-of-the-art high-resolution mesoscale cloud model showed that land-surface moisture significantly affects the timing of onset of clouds and the intensity and distribution of precipitation. In general, landscape discontinuity enhances shallow convective precipitation. Two mechanisms that are strongly modulated by land-surface moisture-namely, random turbulent thermal cells and organized sea-breeze-like mesoscale circulations-also determine the horizontal distribution of maximum precipitation. However, interactions between shallow cumulus and land-surface moisture are highly nonlinear and complicated by different factors, such as atmospheric thermodynamic structure and large-scale background wind. This analysis also showed that land-surface moisture discontinuities seem to play a more important role in a relatively dry atmsophere, and that the strongest precipitation is produced by a wavelength of land-surface forcing equivalent to the local Rossby radius of deformation. A general trend between the maximum precipitation and the normalized maximum latent heat flux was identified. In general, large values of mesoscale latent heat flux imply strongly developed mesoscale circulations and intense cloud activity, accompanied by large surface latent heat fluxes that transport more water vapor into the atmosphere.

Distribution and Peculiarity of Mediterranean Ecosystems

Abstract: The lands of mediterranean scrub or chaparral climate and the ecosystems that have developed in them must be defined in climatic terms. If we attempt to focus on the characteristic core of a mediterranean scrub or chaparral climate three terms stand out, two involving precipitation and one temperature. The most distinctive term involves the concentration of rainfall in the winter half year, November through April in the northern hemisphere and May through October in the southern. Although at a large number of stations, especially in California and Chile, 80 or even 90% of the precipitation occurs in winter, so large a proportion rarely obtains around the Mediterranean Basin itself. The value of at least sixty five percent of the year’s precipitation occurring in the winter half year seems, on the basis of examining a considerable number of station records, to form a satisfactory boundary. Winter rainfall, because of lower evaporation, is more effective in sustaining plant growth than is warm season precipitation; nonetheless, in this climatic region all but favorably located phreatophytic vegetation is subject to drought stress in summer.