Editorial note     

Herman van der Wusten  Olga Gritsai 《GeoJournal》1996,38(1):v-v

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Modelling catchment‐scale erosion patterns in the East African Highlands     

Olga Vigiak  Barrack O. Okoba  Geert Sterk  Sander Groenenberg 《地球表面变化过程与地形》2005,30(2):183-196

Prompt location of areas exposed to high erosion is of the utmost importance for soil and water conservation planning. Erosion models can be useful tools to locate sources of sediment and areas of deposition within a catchment, but the reliability of model predictions of spatial patterns of erosion at catchment scale has seldom been validated against observations. This study aimed to evaluate the performance of a simple empirical model (Morgan, Morgan and Finney model, MMF) in predicting spatial patterns of erosion at two small catchments in the East African Highlands: Kwalei (Tanzania) and Gikuuri (Kenya). Erosion maps predicted by the MMF model were compared with erosion maps obtained by direct survey. In Kwalei, erosion features were especially frequent in fields of annual crops. In Gikuuri, slope was the critical erosion factor, with estimated erosion rates >10 kg m^?2 a^?1 on slopes >18 per cent. Predicted erosion rates were mainly transport‐limited and ranged from <0·01 to 13·50 kg m^?2 a^?1 in Kwalei and 9·29 kg m^?2 a^?1 in Gikuuri. The performance of the MMF model in predicting the spatial patterns of erosion was acceptable in Kwalei, but poor in Gikuuri. However, by excluding the elements at the valley bottoms in Gikuuri Catchment, the performance of the model improved dramatically. The spatial pattern of erosion predicted by the MMF model was driven by the accumulation of surface runoff, which did not consider the possibility of re‐infiltration along the slope. As a result, the MMF erosion patterns predicted by the model increased invariably from the ridges to the valley bottoms, hampering the model suitability for locating areas subjected to high and very high erosion. It is concluded that the model predictions could be substantially improved by introducing a more realistic hydrological component for the prediction of surface runoff along the hill‐slope. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Developing the Next Generation of Community-Based Scholars     

Timothy L. Hawthorne  Olga S. Jarrett 《The Professional geographer》2018,70(2):291-297

As we train the next generation of scholars, we should be cognizant that the academy is increasingly being asked to justify its value to broader society. We discuss ways in which students can prepare for the changing directions of the academy as they participate in a community geography research training program. Our results reveal the impacts of our program, contextualize lessons learned from creating community-based research experiences, and provide data to support a framework for other scholars to develop community-based research training programs.  相似文献   

Improving decision-making activities for meningitis and malaria     

Pietro Ceccato  Sylwia Trzaska  Carlos Pérez García-Pando  Olga Kalashnikova  John del Corral  Rémi Cousin 《国际地球制图》2014,29(1):19-38

Public health professionals are increasingly concerned about the potential impact that climate variability and change can have on infectious disease. The International Research Institute for Climate and Society (IRI) is developing new products to increase the public health community’s capacity to understand, use and demand the appropriate climate data and climate information to mitigate the public health impacts of climate on infectious disease, in particular meningitis and malaria. In this paper, we present the new and improved products that have been developed for: (i) estimating dust aerosol for forecasting risks of meningitis and (ii) for monitoring temperature and rainfall and integrating them into a vectorial capacity model for forecasting risks of malaria epidemics. We also present how the products have been integrated into a knowledge system (IRI Data Library Map Room, SERVIR) to support the use of climate and environmental information in climate-sensitive health decision-making.  相似文献   

Seismic treatment for a maximal credible earthquake in Guwahati city area of northeast India region     

Olga Erteleva  Felix Aptikaev  Saurabh Baruah  Santanu Baruah  Sajal K. Deb  J. R. Kayal 《Natural Hazards》2014,70(1):733-753

Strong ground motion parameters for the Guwahati city area, the capital city of the state of Assam in northeast India, are examined with the help of data accrued from local as well as worldwide network. Empirical relations are proposed for the ground motion parameters as a function of earthquake magnitude, distance, fault type, source depth and velocity characteristics of medium. Seismotectonics of the study region is examined, and a maximum credible earthquake M _S ~ 8.0 is presumed from the Brahmaputra fault, the nearest source zone in the city area. Such great/major event may cause intensity of the of 9.3 with a probability of 0,95 in the Guwahati city during time interval of 500 years. Further, the design spectrum with 67 % confidence level and the synthetic three-component accelerograms are constructed. These results are much relevant and useful for structural engineering to mitigate seismic hazards in the region.  相似文献   

Thermodynamic Model of Uranium and Arsenic Accumulation in Saline Lakes     

Olga GASKOVA  Vitaly ISUPOV  Alexander VLADIMIROV  Stepan SHVARTSEV 《《地质学报》英文版》2014,88(Z1):135-136

正1 Introduction The attractiveness of Shaazgai-Nuur Soda Lake(pH9.2-9.4)as an alternative metal source is explained by the high concentration of dissolved uranium(~1 mg/l)due to the location of water drainage territory within the Tsagan-  相似文献   

A simple method to model the reduced environment of lake bottom sapropel formation     

Gaskova  Olga L.  Strakhovenko  Vera D.  Ermolaeva  Nadezhda I.  Zarubina  Eugene Yu.  Ovdina  Ekaterina A. 《中国海洋湖沼学报》2017,35(4):956-966

The Kambala and Barchin brackish lakes(Baraba steppe,southern West Siberia) contain an organic-rich sapropel layer that was formed in oxygen-depleted waters.We measured the bulk sediment elemental composition,the water chemistry and determined the mineralogical composition and predominant biota species(Diatoms and Cyanobacteria in phytoplankton community respectively) in the lakes.The result indicates that the first lake has a siliceous type of sapropel and the second a carbonaceous one.A computer thermodynamic model was developed for chemical interaction in water-bottom sediment systems of the Kambala and Barchin Lakes.The surface sodium bicarbonate waters are supersaturated with respect to calcite,magnesite(or low Mg-calcite),quartz and chlorite with minor strontianite,apatite and goethite(pH8.9-9.3,Eh 0.3 V).Nevertheless,it is shown that during sapropel deposition,deep silt waters should be anoxic(Eh0 V).The virtual component CH_2O has been used to create an anoxic environment suitable for pyrite formation due to the biotic community impact and abiotic reduction.Thermodynamic calculation has shown that silt water is not necessarily euxinic(anoxic and sulfidic).Depending on Eh,sulfate sulfur can dominate in solution,causing the formation of gypsum together with pyrite.An attempt was made to find a reason for solution supersaturation with respect to Ca and Mg ions due to their complexation with humic acids.  相似文献   

Spatiotemporal multiscale diagnosis model to proactively respond to the multi-country monkeypox virus outbreak in 2022     

Olga De Cos Guerra  Valentín Castillo Salcines  David Cantarero Prieto 《Transactions in GIS》2023,27(8):2175-2196

This research analyzes the spatiotemporal trend of 23,121 monkeypox virus cases in the multi-country outbreak that affected 82 countries from January 2022 to July 2022. The spatiotemporal trends analysis is developed using open data and GIS to model 3D bins and emerging hot spots globally (data by country) and nationally (data by region) for hardest hit countries, like the USA and Spain. The implemented methodology distinguishes between problem areas —as significant hot spots— and countries with no pattern. Results show consecutive hot spot patterns in Western Europe and high location quotients in North America. Factually, the countries with consecutive patterns record 16,494 cases, that is, 71.34% of the cases, where 7.63% of the world population live. At the national level, in the analysis of the USA and Spain, the results reveal regional differences with significative hot spots in California and on the East Coast of the USA and the Mediterranean coast of Spain. The proposed methodology facilitates the monitoring of the spatiotemporal evolution of monkeypox cases and is scalable and replicable using non-arbitrary and statistical parameters. The findings indicate problematic zones in real-time, enabling policymakers to develop focused interventions and proactive strategies to mitigate the future risk of monkeypox.  相似文献