Search results for "Precipitation"
showing 10 items of 826 documents
Precipitation Pulses and Soil CO2 Emission in Desert Shrubland of Artemisia ordosica on the Ordos Plateau of Inner Mongolia, China
2009
National Natural Science Foundation of China [40730105, 40501072, 40673067]; National Key Basic Research Program (973 Program) of China [2002CB412503]; Chinese Academy of Sciences [KZCX2-YW-149]
Seasonal variability in silicate weathering signatures recorded by Li isotopes in cave drip-waters
2021
Abstract Silicate weathering is a critical process in Earth’s carbon cycle, but the fundamental controls on weathering are poorly understood and its response to future climate change is uncertain. In particular, the potential for changes in seasonality or extreme weather events to control silicate weathering rates or mechanisms has been little studied. Here, we use lithium (Li) isotope measurements in bimonthly sampled drip-waters from two caves in the Yorkshire Dales (U.K.) to assess the response of silicate weathering processes to changes in temperature and hydrology over seasonal timescales. While the caves are contained in limestone bedrock, the drip-water Li isotope signal predominantl…
El Niño in the Eocene greenhouse recorded by fossil bivalves and wood from Antarctica
2011
[1] Quasi-periodic variation in sea-surface temperature, precipitation, and sea-level pressure in the equatorial Pacific known as the El Nino – Southern Oscillation (ENSO) is an important mode of interannual variability in global climate. A collapse of the tropical Pacific onto a state resembling a so-called ‘permanent El Nino’, with a preferentially warmed eastern equatorial Pacific, flatter thermocline, and reduced interannual variability, in a warmer world is predicted by prevailing ENSO theory. If correct, future warming will be accompanied by a shift toward persistent conditions resembling El Nino years today, with major implications for global hydrological cycles and consequent impact…
Recent Change—Atmosphere
2015
This chapter examines past and present studies of variability and changes in atmospheric variables within the North Sea region over the instrumental period; roughly the past 200 years. The variables addressed are large-scale circulation, pressure and wind, surface air temperature, precipitation and radiative properties (clouds, solar radiation, and sunshine duration). Temperature has increased everywhere in the North Sea region, especially in spring and in the north. Precipitation has increased in the north and decreased in the south. There has been a north-eastward shift in storm tracks, which agrees with climate model projections. Due to large internal variability, it is not clear which a…
Moroccan speleothem and tree ring records suggest a variable positive state of the North Atlantic Oscillation during the Medieval Warm Period
2013
We present a magnesium (Mg) and strontium (Sr) record from an aragonitic speleothem (Grotte de Piste, Morocco, 34°N; 04°W) providing a reconstruction of effective rainfall from 619 to 1962 AD. The corresponding drip site was monitored over 2 yr for drip water Mg/Ca and Sr/Ca ratios. Results show evidence for prior aragonite precipitation, which can explain negative correlations between speleothem Mg and Sr concentrations. The data shown here have important climate implications concerning the evolution of the North Atlantic Oscillation (NAO). A comparison of the stalagmite data from Grotte de Piste with an updated tree ring based drought reconstruction from Morocco and other NAO related pro…
Isotope composition of rain water, well water and fumarole steam on the island of Vulcano, and their implications for volcanic surveillance
1992
Abstract Water samples from eight wells in the Vulcano Porto area and fumarole steam from the crater of Vulcano (Southern Italy) were collected at monthly intervals over a two-year period from February 1987 to January 1989. Samples of bulk precipitation were also collected in three points at Vulcano Porto and Vulcano Piano (island of Vulcano) and Castroreale (Tyrrhenian coast of Sicily), again at monthly intervals. The weighted mean isotopic composition of rain water on Vulcano is δ D =−32‰ , and δ D 18 O =−6.4‰ . Results for well waters tend to support the existence of at least two water bodies: one of purely meteoric water and the other of brackish thermal water. An intermediate water bod…
Late Quaternary Variations in the South American Monsoon System as Inferred by Speleothems – New Perspectives Using the SISAL Database
2018
Here we present an overview of speleothem δ18O records from South America, most of which are available in the Speleothem Isotopes Synthesis and Analysis (SISAL_v1) database. South American tropical and subtropical speleothem δ18O time series are primarily interpreted to reflect changes in precipitation amount, the amount effect, and consequently history of convection intensity variability of convergence zones such as the Intertropical Convergence Zone (ITCZ) and the South America Monsoon System (SAMS). We investigate past hydroclimate scenarios in South America related to the South American Monsoon System in three different time periods: Late Pleistocene, Holocene, and the last two millenni…
Potential Impact of Global Climate Change on Species Richness of Long-Distance Migrants
2003
Little evidence exists demonstrating that global climate change leads to systematic changes in the struc- ture of ecological communities. For avian communities, one would expect warmer winters to lead to declines in numbers of long-distance migrants if resident birds benefit from warmer winters and impose increasing competi- tive pressure on migrants. To study the potential influence of global climate change on long-distance migrants, we correlated the number of all species of land birds and the number and proportion of long-distance migrants, short- distance migrants, and residents in 595 grid cells across Europe. We used mean temperature of the coldest month, mean spring temperature, and …
Impact of Holocene climate variability on lacustrine records and human settlements in South Greenland
2015
Due to its sensitivity to climate changes, south Greenland is a particularly suitable area to study past global climate changes and their influence on locale Human settlements. A paleohydrological investigation was therefore carried out on two river-fed lakes: Lake Qallimiut and Little Kangerluluup, both located close to the Labrador Sea in the historic farming center of Greenland. Two sediment cores (QAL-2011 and LKG-2011), spanning the last four millennia, were retrieved and showed similar thin laminae, described by high magnetic susceptibility and density, high titanium and TOC / TN atomic ratio, and coarse grain size. They are also characterized either by inverse grading followed by nor…
Precipitation and Temperature
2016
Climatological studies indicate that climate change lead to an increase in the mean global temperature of around 0.5 °C until the end of the twentieth century. This warming impacts the atmospheric humidity, wind, radiation, and precipitation. However, the magnitude of changes is not equally distributed over the globe but differs markedly with regions, making a regionalization of the global information essential. The GLOWA-Danube project follows such a downscaling approach with the focus on the drainage basin of the Upper Danube River.