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.

Climate change scenarios for seasonal precipitation in South America from IPCC-AR4 models

Abstract: [1] A subset of climate simulations of the 20th century from the IPCC-AR4 is analyzed to assess the ability of these models to reproduce the observed climatological seasonal precipitation in South America during the period 1970–1999. Changes of the model climatology in a climate change scenario (SRESA1b) for the period 2070–2099 are also discussed. Results show that models are able to reproduce the main features of the precipitation seasonal cycle over South America, although the precipitation in the SACZ region and the precipitation maximum over southeastern South America observed during the cold season are not well- represented. There is a general consensus among models that the precipitation changes projected are mainly: i) an increase of summer precipitation over southeastern subtropical South America; ii) a reduction of winter precipitation over most of the continent; and iii) reduction of precipitation in all seasons along the southern Andes.

Observational evidence that soil moisture variations affect precipitation

Abstract: Land-atmosphere feedback, by which precipitation-induced soil moisture anomalies affect subsequent precipitation, may be an important element of Earth's climate system, but its very existence has never been demonstrated conclusively at regional to continental scales. Evidence for the feedback is sought in a 50-year observational precipitation dataset covering the United States. The precipitation variance and autocorrelation fields are characterized by features that agree (in structure, though not in magnitude) with those produced by an atmospheric general circulation model (AGCM). Because the model-generated features are known to result from land-atmosphere feedback alone, the observed features are highly suggestive of the existence of feedback in nature.

Precipitation Modification By Major Urban Areas

Abstract: Historical weather records at eight American urban areas of varying size, type, and climate were studied for indications of inadvertent precipitation modification. The six largest cities all had experienced warm seasonal rainfall increases of 9 to 17% during the 1955–70 period. The increases in the Midwest cities occurred largely with cold frontal systems, but in the coastal cities they were largely during air mass (non-frontal) conditions. The Midwest increases also were found to occur as enhancement, not initiation, of moderate to heavy rain days. Significant increases in summer thunder-day frequencies (13 to 41%,) and hail-day frequencies (90 to 450%) were found at the six largest cities, and the increases occurred largely in the morning hours. The typical locations of maxima in the Midwest cities were thunder over and near the city, and rain and hail 25 to 55 km downwind. The maxima of all events in coastal cities were in or near the city. Overall, the results suggest that urban precipitation...

Preliminary Study on Signal, Impact and Foreground of Climatic Shift from Warm-Dry to Warm-Humid in Northwest China

Abstract: A rapid, high amplitude global climatic warming would speed global water cycle and strengthen rainfall and evaporation. Climatic warming and drying course were dominated in past about 100 years since the end of Little Ice Age in Northwest China. The strong signals of climatic shift to warm humid pattern have been appearing in the western part of Chinese Tianshan Mountains and neighborhood regions including Northern Xinjiang since 1987. Precipitation, meltwater of glacier and runoff of rivers increase continuously , and results in lake level rising, flood damaged magnification and intensified, vegetation coverage extending and dust storm weaken in western parts of Northwest China. In the other areas of Xinjiang, and the middle and western section of Qilian Mountains, the precipitations and runoff of rivers have also an increasing tendency. How is the foreground of climatic shift to warn humid conditions, it is just restricted to decadal fluctuation, or possibility to century scale shift trend, and is just limited to western Tianshan or could extend and/or wholly Northwest China down to North China?Using the results of regional climatic model simulation from IPCC and China Assessment Report published, predicting river runoff regime and similar paleoclimate scenarios for the Northwest China are analysed and discussed, and the trend of shifting warm humid climate can be fixed in recent future. However, uncertain of projected results remain, and rating and magnitude of climatic shift extending in temporal and spatial scales can not at present be projected in detail and in being exactitude.