Land desertification that is an important content in the global change research is the one of most serious ecological problems all over the world. It is not only the threat to the survival of the human environment, but also the important factor to restrict the development of the global economy and affect Social stability. If we don’t take fundamental measures, the process of land desertificationwill not stop automatically, but will intensify to develop.We should start from the inherent attributes of the land desertification for learning to its type and extent. The comprehensive application and research of the Remote Sensing Data and Multiple Geo-information can be show attributes and inherent feature of the objects with a variety of ways and different scales. It’s very advantaged for Remote Sensing information to distinguish the object with their differentia of electromagnetic radiation features, but also it have some limitations. Practice has proved that we must relate Remote Sensing data to Multiple Geo-information that contain Geological data and Geochemical data with addition of the difficulty of geological work, and then we truly understand the nature of the objects and relation each other, also to be satisfied with the application of geological effects.
This article use the west of Ji Lin Province as study area. It make an estimate to desert land in working area as a whole with Remote Sensing Data (2007 ETM) and Geochemical Data (the results of 1:200000 soil geochemical survey in the west of Ji Lin Province).
Major work is as follows:(1) The classification of desert land.We obtain the information of land desertification in the west of Ji Lin Province by the ways of unsupervised classification and supervised classification, and then compare the results of both so that to separate accurately desert land and undesert land. The result indicates that the method of supervised classification is more accurate.(2) Enhance the information of Clay minerals among Remote Sensing Data. The special configuration of the objects fix on their Physical and Chemical character. We can analyse the inherent attributes after studying their spectrum character. Clay minerals which play an important role in extent of Land Desertification is an important part of soil composing. But vegetation and clay minerals have similar characteristic absorbable spectrum because the west of Ji Lin Province locate moist area. We should make use of Band Ratio and Principal Components to avoid vegetation information that would disturb clay minerals information in Remote Sensing Data as a whole hog so that we can analyse accurately the negative correlation between the extent of desertification and content of clay minerals.(3) Research methods of combination and classification of elements about Geochemical Data.We make use of Genealogy Cluster Analysis to combine and classify various elements among Geochemical data. The establishment of equal deep image of minerals content such as Quartz, Clay Minerals, Carbonate and so on could reflect directly the distribution of various minerals about Geochemical Data. It validates the seasonable of classification through contrasting Remote Sensing Image.(4) Complete the classification evaluation of desert land and find the variety rule between Remote Sensing spectrum and mineral content.The substance composing of different degrees of desert land is different. There is a close relationship between mineral content and spectral characteristics. We can found the association of both after establishing relevant model of Remote Sensing Spectral Profile image and equal deep image of minerals content.This article first study on Remote Sensing of the degree of land desertification to study area by the ways of combining geochemical data. It’s also the innovation point. It not only has done the evaluation of distribution and degree of desertification land, but also has realized semi-quantitative analysis of clay minerals to desertification land of different degrees. Reached the conclusions as follows:(1) It’s a negative correlation between the extent of desertification and content of clay minerals. The more serious desertification, the less content of clay minerals. There is may be a potential desertification to crops and grassland that contain less clay minerals.(2) The contain of Quartz is more than 42.115077% and the contain of clay minerals is less than 6.410923% to desert land which degree is serious; The contain of Quartz is 39.673305～42.115077% and the contain of clay minerals is 6.410923～8.557119% to desert land which degree is moderate; The contain of Quartz is 34.789760～39.673305% and the contain of clay minerals is 8.557119～10.414073% to desert land which degree is mild.
Measuring carbon emissions is crucial for planning a response to climate change. But scientists have so far struggled to keep track of the world’s carbon stocks and how they vary.
At the Carnegie Airborne Observatory, he has developed a lidar (light detection and ranging) system based on laser technology that is flown over the tropics to measure how much carbon is trapped in the forests, and where deforestation, illegal logging and mining activities are releasing it.
This video shows what pilots can see from above the forest, and how the system turns aerial imagery into colourful, animated carbon maps.
Implementation of Drought Early-warning System over IRAN (DESIR)
Iran’s precipitation is approximately one third of global average and distribution of the monthly rainfall has been changed in recent years. Water scarcity has many environmental and socio-economical impacts over Iran. Unlike to the floods that have limited coverage areas, water scarcity impacts cover vast regions. By increasing global mean temperature, drought and population, water and its consumption has become important. This may even become more significant in those countries where the volume of rainfall is limited. Occurrence of drought is one of the main reasons of the water crisis. Implementation of a drought early warning system is the most important priority for I. R. of Iran Meteorological Organization (IRIMO).
Development of EO indicators for the Dynamic of Desertification in Southern Africa
This is a one year project involving a partnership with ISEGI, Mondelane U. and U. DELFT.
The aim of this project is the analysis of new dynamics of desertification in the region Southern Africa ( Mozambique , Zimbabwe and Northern part of South Africa ) by using and implementing the main achievements of the DW –E, a methodology developed by CERENA and a standard processing chain over Earth Observation data, in order to produce desertification indicators, allowing the monitoring of areas subject or in risk of desertification.
A second objective is to propose new methods for integration of EO data with different spatial and spectral resolutions, namely the new ESA Proba- V mission with products ranging in spatial resolution from 100m to 1km , and new field data in particular the survey and risk map of natural disasters made between 2010 and 2011 for Mozambique.
We review the evidence that connects drought and desertification in the Sahel with climate change past, present and future. Advances in climate modeling point to the oceans, not land, as the cause of the recent persistence of drought in the Sahel.
The current generation of global climate models reproduces the spatial extent, continental in scale, and the timing and duration of the shift to dry conditions that occurred in the late 1960’s given knowledge of observed surface oceanic conditions only.
The pattern statistically and dynamically associated with drought is one of warming of the tropical oceans, especially the Pacific and Indian Oceans, superimposed on an enhanced warming of the southern compared to the northern hemisphere most evident in the Atlantic.
These models, which include a prognostic description of land surface and/or vegetation, albeit crude, indicate that positive feedbacks between precipitation and land surface/cover may act to amplify the ocean-forced component of continental climate.
Despite the advances made in understanding the recent past, uncertainty dominates as we move forward in time, to the present, partial greening of the Sahel, and to the future of climate change projections.
Monitoring land-cover changes in semi-arid regions: remote sensing data and field observations in the Ferlo, Senegal
by A. Diouf and E.F. Lambin
Dryland degradation rarely translates into linear, declining trends in vegetation cover due to interannual climatic variability. Appropriate indicators of land-cover modifications need to be defined for semi-arid regions.
Our hypothesis is that degradation can be measured by:
(1) a decrease in the resilience of vegetation to droughts;
(2) a decrease in rain-use efficiency; and
(3) a modification of floristic composition.
The objective of this paper is to test the relationships between a remotely sensed indicator of vegetation, rainfall data and field measurements of biomass and floristic composition.
The study was based on field measurements of vegetation conditions covering a period of 10 years, in the semi-arid region of the Ferlo in Senegal.
Our results indicate that land-cover modifications in the Ferlo are best measured by changes in rain-use efficiency. No consistent trend in the relative abundance of grass species was visible at the scale of the decade, even on the two sites affected by degradation. Just after a drought, a given increase in rainfall results in less biomass production than is the case for normal years.
Andhra Pradesh State Remote Sensing Applications Centre has revealed an alarming increase in the spread of sand dunes, as 0.32 sq. km of land is being covered by sand dunes every year since the last 10 years.
The study revealed different signs of desertification and land degradation in the study area as judged by change in patterns of land use and land cover types. These changes indicated an increase of degrading land, vegetation cover, sandy soil and sandy clay in the study area. Desertification is one of the main problems threatening the agricultural production The study aimed at monitoring and assessing desertification in area, in addition to investigating the potential use of remote sensing and GIS) in assessing and monitoring sand encroachment and vegetation degradation as desertification indicators in the semi-arid environment.