نتایج جستجو برای: climate changes
تعداد نتایج: 1011976 فیلتر نتایج به سال:
Climate is the most important factor which control desertification .In order to detect climate changes in desert zones, time trend analysis is applied to extreme indices in Kashan station using extreme climate index software (ECIS). Results show significant trends in extreme indices during the past decade 1995-2004 and the pronounced warming is associated with a negative trend in cold extremes....
Investigation on climate change is coordinated by the Intergovernmental Panel on Climate Change (IPCC), which has the delicate task of collecting recent knowledge on climate change and the related impacts of the observed changes, and then developing a consensus statement from these findings. The IPCC's last review, published at the end of 2007, summarised major findings on the present climate s...
Climate changes influencing forest ecosystems include increased air temperatures and CO2 concentrations as well as droughts and decreased water availability. These changes in turn effect changes in species composition of both host plants and pathogens. In the case of Armillaria, climate changes cause an increase in the activity of individual species and modify the growth of rhizomorphs, increas...
Since climate change is regarded as a serious threat to different parts of life cycle, separation of factors intensifying this phenomenon seems necessary. This research has investigated the temperature and precipitation trend using the multiple trend test in the upstream Karkheh basin located in west of Iran. For this purpose, two-dimensional graphs of temperature and precipitation anomalies of...
agricultural sector will be most affected by climate change due to its extensive interaction with the environment. and as a result of changing production conditions, community welfare is changed. this study attempted at understanding the welfare effects of changes in climate parameters on the wheat product. therefore, the yield functions were initially estimated. supply, demand and import funct...
Changes in body size and breeding phenology have been identified as two major ecological consequences of climate change, yet it remains unclear whether climate acts directly or indirectly on these variables. To better understand the relationship between climate and ecological changes, it is necessary to determine environmental predictors of both size and phenology using data from prior to the o...
This study investigates the effect enclosure on some soil characteristics in two different climates; include semi-arid climate (Incheh boron region) and Cold climate of semi-humid (Chahar bagh) in Golestan province. In order to do soil sampling by the systematic-random methods, 5 transect were used in each areas and Physical and chemical properties were measure. T-test method was used in order ...
palaeoclimatology is a basic approach for the neolithic archaeology. the world-wide climate changes during the holocene ca. 10th millennia bc was an introduction to the neolithic revolution and the emergence of early villages. early holocene climate oscillations changed the biogeography of iran. consequently, its temperature, fauna and flora had been changed during ca. 12800- 3500 bc; and final...
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