Holocene Records of Rainfall Variation and Associated ITCZ Migration from Stalagmites from Northern and Southern Oman

2004 ◽  
pp. 259-287 ◽  
Author(s):  
Dominik Fleitmann ◽  
Stephen J. Burns ◽  
Ulrich Neff ◽  
Manfred Mudelsee ◽  
Augusto Mangini ◽  
...  
Keyword(s):  
Rainfall Variation

scholarly journals Effects of water and soil conservation works on runoff and sediment variation in the areas with high and coarse sediment yield of the middle Yellow River

2018 ◽  
Vol 38 ◽  
pp. 01033
Author(s):  
Wei Ying Sun ◽  
Pan Zhang ◽  
Li Li ◽  
Jiang Nan Chen
Keyword(s):  
Sediment Yield ◽  
Water Conservation ◽  
Human Activities ◽  
Soil Conservation ◽  
Yellow River ◽  
Soil And Water Conservation ◽  
Contribution Rate ◽  
Rainfall Variation ◽  
Runoff Reduction ◽  
Soil And Water

The areas with high and coarse sediment yield of the middle Yellow River is well known for its severe erosion, high sediment yields. Since 1982 when the 8 key soil and water conservation harnessing regions has been built, the ecological environment has been gradually improved and the amount of sediment and runoff entering the Yellow River has been reduced continuously. Some researchers considered that it was owing to the water and soil conservation works (WSCW), while others believed that it was caused by the rainfall variation, but this has not been quantified for the effect respectively. This paper deals with the effects of WSCW on runoff and sediment variation. The study has been carried out in the Sanchuanhe River watershed, where was listed as one of the 8 key soil and water conservation harnessing regions. The results show that the contribution rate of human activities was 80.2% after 1st harnessing stage (1970-1979), 43.0% after 2nd harnessing stage (1980-1989), in 3rd harnessing stage (1990-1996) it reached 98.4%, and was 44.8% after 4th harnessing stage (1997-2006). With regard to the influence on runoff reduction in the watershed, the contribution rate of human activities was 62.5% compared with the natural factors after 1st harnessing stage (1970-1979), 28.4% after 2nd harnessing stage (1980-1989), in 3rd harnessing stage (1990-1996) it reached 69.6%, and was 37.0% after 4th harnessing stage (1997-2006). The results revealed that human activities exerted the largest effects on the sediment reduction and explained 66.6% of the variation in the specific sediment yield. This study suggests that a combination of human activities and rainfall variation effectively reduces runoff and sediment delivery of the Loess Plateau. Generally The runoff reduction and contribution of rainfall variation to runoff reduction in this area were as large as human activities. After many years' harnessing the great benefit have been obtained in water and soil loss control in this watershed.

scholarly journals Natural and Managed Grasslands Productivity during Multiyear in Ex-Arable Lands (in the Context of Climate Change)

Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 215
Author(s):  
Liudmila Tripolskaja ◽  
Asta Kazlauskaite-Jadzevice ◽  
Virgilijus Baliuckas ◽  
Almantas Razukas
Keyword(s):  
Climate Change ◽  
Soil Properties ◽  
Dry Matter ◽  
Arable Land ◽  
Rainfall Amount ◽  
Rainfall Variation ◽  
Global Issue ◽  
Term Change ◽  
The Impact

Ex-arable land-use change is a global issue with significant implications for climate change and impact for phytocenosis productivity and soil quality. In temperate humid grassland, we examined the impact of climate variability and changes of soil properties on 23 years of grass productivity after conversion of ex-arable soil to abandoned land (AL), unfertilized, and fertilized managed grassland (MGunfert and MGfert, respectively). This study aimed to investigate the changes between phytocenosis dry matter (DM) yield and rainfall amount in May–June and changes of organic carbon (Corg) stocks in soil. It was found that from 1995 to 2019, rainfall in May–June tended to decrease. The more resistant to rainfall variation were plants recovered in AL. The average DM yield of MGfert was 3.0 times higher compared to that in the AL. The DM yields of AL and MG were also influenced by the long-term change of soil properties. Our results showed that Corg sequestration in AL was faster (0.455 Mg ha−1 year−1) than that in MGfert (0.321 Mg ha−1 year−1). These studies will be important in Arenosol for selecting the method for transforming low-productivity arable land into MG.

scholarly journals Feedback of trees on nitrogen mineralization to restrict the advance of trees in C4 savannahs

2015 ◽  
Vol 11 (8) ◽  
pp. 20150572 ◽  
Author(s):  
Steven I. Higgins ◽  
Moagi Keretetse ◽  
Edmund C. February
Keyword(s):  
Remote Sensing ◽  
Nitrogen Mineralization ◽  
Negative Feedback ◽  
Nitrogen Limitation ◽  
Seasonal Pattern ◽  
Seasonal Temperature ◽  
Rainfall Variation ◽  
Progressive Nitrogen Limitation

Remote sensing studies suggest that savannahs are transforming into more tree-dominated states; however, progressive nitrogen limitation could potentially retard this putatively CO 2 -driven invasion. We analysed controls on nitrogen mineralization rates in savannah by manipulating rainfall and the cover of grass and tree elements against the backdrop of the seasonal temperature and rainfall variation. We found that the seasonal pattern of nitrogen mineralization was strongly influenced by rainfall, and that manipulative increases in rainfall could boost mineralization rates. Additionally, mineralization rates were considerably higher on plots with grasses and lower on plots with trees. Our findings suggest that shifting a savannah from a grass to a tree-dominated state can substantially reduce nitrogen mineralization rates, thereby potentially creating a negative feedback on the CO 2 -induced invasion of savannahs by trees.

scholarly journals Estimating urban flood risk – uncertainty in design criteria

2015 ◽  
Vol 370 ◽  
pp. 3-7 ◽  
Author(s):  
M. Newby ◽  
S. W. Franks ◽  
C. J. White
Keyword(s):  
Data Analysis ◽  
Flood Risk ◽  
Rainfall Intensity ◽  
Design Criteria ◽  
Climate Change Scenarios ◽  
Urban Flood ◽  
Frequency Distributions ◽  
Rainfall Variation ◽  
Design Rainfall ◽  
Australian Rainfall

Abstract. The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1 : 5 year ARI correlates with an 18.13% AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20% AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.

scholarly journals Rainfall Variation: Implication on Cocoa Yield in Ondo State, Nigeria

2018 ◽  
pp. 16-25
Keyword(s):  
Tropical Rainforest ◽  
Line Graph ◽  
Yield Data ◽  
Rainfall Variation ◽  
Cash Crops ◽  
Ondo State ◽  
R Value ◽  
The Relationship ◽  
Cocoa Plantation ◽  
Cocoa Yield

Cocoa is known as one of the notable cultivated cash crops of the tropical rainforest of the world that is rain dependent. The study examines the effect of rainfall variation on the yield of cocoa plantation in Ondo State, Nigeria. Data used for the study includes the rainfall data of 15 years from 2000 to 2014 collected from Ondo state agro climatological office as well as cocoa yield data for the same period of time from Ondo State ministry of agriculture and forest resources. Descriptive statistical method was employed to determine the relationship between both variables in which the result shows direct relationship between rainfall and cocoa yield. Results were presented using bar charts and line graph for the time series analysis of the variables. Linear regression statistical analysis was used to predict cocoa yield with certain amount of rainfall with the correlation coefficient ‘r’ value of 0.97 which implies that rainfall changes go a long way to determine the same variation trend in the cocoa yield. Though, not only the quantity of rainfall within the range of rainfall required for the growth of this crop affect the yield but its distribution. A little millimeter of rainfall above or below the required range of rain for cocoa plantation greatly affects cocoa yield.

scholarly journals THE INFLUENCE OF THE BRAZILIAN CERRADO DEFORESTATION IN GRAIN CULTURE AND ITS CONSEQUENCES TO LOSSES THE SOIL IN THE CACHOEIRA DOURADA RESERVOIR REGION – CENTRAL - WESTERN BRAZIL

2013 ◽  
pp. 01
Author(s):  
João Batista Pereira Cabral ◽  
Valter Antonio Becegato ◽  
Francismário Ferreira dos Santos
Keyword(s):  
Annual Cycle ◽  
Annual Rainfall ◽  
Brazilian Cerrado ◽  
Rainfall Distribution ◽  
Rainfall Variation ◽  
Influence Area ◽  
Average Annual Rainfall ◽  
Average Rainfall ◽  
Soil Preparation ◽  
Erosivity Index

The erosivity index (EI30) and its spatialization were determined for the contribution basins of the Cachoeira Dourada hydroelectric system reservoir, located between the states of Goiás and Minas Gerais and limited by coordinates 640000-760000 m W and 7910000-7975000 m N. Average monthly and annual rainfall data corresponding to eight localities and to a 30-year period were treated. It was observed that in this period the average annual rainfall was 1441 mm, the highest and lowest indexes having occurred respectively in January and July (7.5 mm). EI30 varied from 7100 to 8500 MJ mm (ha h)-1. The most representative period was October to March, corresponding to 7880.3 MJ mm (ha h)-1and 94% of the average annual EI30. The average rainfall variation coefficient for all stations was 82.73%. There is an irregular rainfall distribution in the region and consequently a non-uniform spatialization of the erosivity indexes within the influence area of the reservoir. The highest rainfall values coincide with the period of soil preparation and development of annual-cycle plants, mainly soybean and corn.

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