نتایج جستجو برای: arid and semiarid climate

تعداد نتایج: 16861318  

2008
Ali A. Sabziparvar

Over the last two decades, using simple radiation models has been an interesting task to estimate daily solar radiation in arid and semiarid deserts such as those in Iran, where the number of solar observation sites is poor. In Iran, most of the models used so far, have been validated for a few specific locations based on short-term solar observations. In this work, three different radiation mo...

Land degradation in arid and semi-arid regions caused by climate change and human activities makes it more susceptible to desertification. The aim of this research is assessing the intensity of desertification in Roudab plain of Sabzevar city using IMDPA model. So two criteria of climate and water as the main criteria affecting desertification process were considered based on field observations...

2012
Ming-Han Li Chan Yong Sung Myung Hee Kim Kung-Hui Chu

bioretention, its applicability to a hot and semiarid region has rarely been evaluated. Existing manuals are developed primarily by studies from temperate-climate regions and focus on residential–commercial uses (3–5). Therefore, bioretention research that addresses hotclimate areas and large-scale highway conditions is needed. To apply bioretention on highway roadsides, design specifications s...

Journal: :جغرافیا و توسعه ناحیه ای 0
موسوی بایگی موسوی بایگی اشرف اشرف

the solar radiation received by earth surface is one of the most applicable parameter that is so important in hydrology, agriculture, meteorology and climatological modeling. because of very expensive instrument for measuring the radiation, researchers suggested many different experimental equations to estimate this parameter in different climate. seven models which are calibrated for semi-arid...

Journal: Desert 2017

Hydrological processes and their spatial distribution directly are relevant to climate, topography, geology, and land use in the watershed. Therefore, use of a model whit integrity and high performance for simulating the process in deferent watersheds is very important. In this study was assessment performance of semi-distributed SWAT model in simulating hydrology processes in three watersheds ...

Journal: :تحقیقات آب و خاک ایران 0
علیرضا راهب دانشگاه تهران احمد حیدری دانشگاه تهران شهلا محمودی دانشگاه تهران

soil genesis and evolution studies are based on well understanding of geochemical processes involved in pedogenic processes and formation of soil. parent materials are main factors controlling soil properties in arid and semiarid regions. in this study, physicochemical and geochemical properties of 6 selected soil profiles developed on basalt rocks along arid (eshtehard), semiarid (qazvin) and ...

2015
Xiaolin Zhang Yulian Tan Ang Li Tingting Ren Shiping Chen Lixin Wang Jianhui Huang

Both water and nitrogen (N) availability have significant effects on ecosystem CO2 exchange (ECE), which includes net ecosystem productivity (NEP), ecosystem respiration (ER) and gross ecosystem photosynthesis (GEP). How water and N availability influence ECE in arid and semiarid grasslands is still uncertain. A manipulative experiment with additions of rainfall, snow and N was conducted to tes...

2004
John L. Wilson Huade Guan

In semiarid climates, a significant component of recharge to basin aquifers occurs along the mountain front. Traditionally called “mountain-front recharge” (MFR), this process has been treated by modelers of basins as a boundary condition. In general, mountain-front recharge estimates are based on the general precipitation characteristics of the mountain (as estimated, e.g., by the chloride mas...

2006
S. C. HART C. A. GEHRING R. J. DECKERT

1. Previous studies in humid forests have shown that the 13 C and 15 N isotopic composition differs between ectomycorrhizal (ECM) and saprotrophic (SAP) fungi, and that this ECM–SAP ‘divide’ may provide a useful tool for evaluating fungal trophic status. 2. We evaluated whether this method could delineate the trophic status of fungi in two semiarid, temperate forests of the south-western USA. T...

Journal: :Ecological applications : a publication of the Ecological Society of America 2011
Sharon J Hall Ryan A Sponseller Nancy B Grimm David Huber Jason P Kaye Christopher Clark Scott L Collins

Rates of nitrogen (N) deposition have increased in arid and semiarid ecosystems, but few studies have examined the impacts of long-term N enrichment on ecological processes in deserts. We conducted a multiyear, nutrient-addition study within 15 Sonoran Desert sites across the rapidly growing metropolitan area of Phoenix, Arizona (USA). We hypothesized that desert plants and soils would be sensi...

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