نتایج جستجو برای: gully morphology

تعداد نتایج: 146786  

2002
Sarah T. Stewart Francis Nimmo

[1] Fresh gully-like features on Mars strongly suggest that fluid flowed on the surface in the recent past. Here we consider the possibility that CO2 vapor-supported flows formed the gullies. We find that neither condensed CO2 nor CO2 clathrate hydrate are likely to accumulate in significant quantities in the Martian crust. In addition, if condensed CO2 were present under lithostatic pressures,...

2007
M. A. Galang C. R. Jackson L. A. Morris D. Markewitz E. A. Carter

The Piedmont region in the United States has been eroded and gullied due to deforestation and cultivation during the 1700 and 1800. Currently, a majority of these gullies are under forest vegetation and appear stable; however, neither the hydrology of these gullies, nor their sediment contribution to surface waters, has been quantified. This study instrumented eight gullies ranging in size from...

Extended Abstract Introduction: Gully erosion is the most severe type of water erosion, which causes large damage in the watersheds. To determine the risk of this type of erosion, it is necessary to estimate its severity and specify the distribution of the risk of erosion in the watershed. One of the models used to estimate the gully erosion is REGEM model, but accurate estimation of erosion r...

2001
J. D. Opsomer Z. Wu R. Cruse T. Isenhart V. Sitzmann T. J. Jacobsen J. Y. Kim C. Botts

This article describes the sampling design, survey methodology and findings of a natural resources survey conducted in the Rathbun Lake Watershed in Southern Iowa in 1999-2000. The goal of the survey was to quantify the erosion from all sources on agricultural lands and the ecological health of streams for each of 61 subwatersheds in the area. A total of 183 plots of approximately 160 acres in ...

2006
P.K.E. Pellikka B.J.F. Clark T. Sirviö K. Masalin

This paper presents environmental change monitoring in the Taita Hills, Kenya applying SPOT XS satellite imagery, aerial photography and digital camera data. The paper presents the data, methods for atmospheric correction, and results from land cover change detection and soil erosion change detection. The results indicated that gully density has doubled in the test sites during the observation ...

Journal: :Memoirs of the National Museum of Victoria 1970

2009
G. A. Morgan J. W. Head J. L. Dickson D. R. Marchant

Introduction: The discovery of gullies on Mars [1,2] resulted in a wide variety of proposed candidate mechanisms for formation but ensuing analyses have shown very strong latitude and orientation dependencies on their distributions [3-6]. These constraints have been interpreted to require: 1) a volatile on or near the surface as a source of liquid water, and 2) insolation and slope orientation ...

2009
K. J. Kolb A. S. McEwen J. D. Pelletier

Introduction: Martian gullies are defined by [1] to be slope features comprised of an upslope alcove, a midslope channel, and a downslope depositional fan. Due to their relative youth and similarities to waterrelated features on Earth, the Martian gullies have attracted much attention since their discovery by the Mars Orbiter Camera [1]. Many erosional agents for the gullies have been proposed ...

Journal: :Catena 2021

Abstract Gully mapping techniques successfully identify gullies over a large range of breadths and depths in complex landscapes but practices for estimating gully volumes need further development. gap-interpolation estimation volume does not often factor landscape microtopography the generation new surface. These approaches can thus overestimate classical volumes, averaging depressions, or unde...

ژورنال: :پژوهش های دانش زمین 0
امیر صفاری دانشیار ژئومورفولوژی، دانشگاه خوارزمی مهدی احمدی دانشجوی دکتری ژئومورفولوژی و مدیریت محیط، دانشگاه خوارزمی سعید رحیمی هرآبادی دانشجوی دکتری ژئومورفولوژی و مدیریت محیط، دانشگاه خوارزمی

شناسایی عوامل موثر در گسترش فرسایش خندقی و پهنه بندی آن یکی از ابزارهای اساسی و مهم جهت مدیریت و کنترل این پدیده و انتخاب مناسب ترین گزینه در مقابله با گسترش این پدیده می باشد. از این رو هدف از این پژوهش انتخاب مهمترین معیارهای تاثیرگذار در پهنه بندی خطر فرسایش خندقی با استفاده از دو روشahp و anp، مشخص کردن نوع کاربری هایی که در محدوده مناطق با حساسیت بسیار زیاد و زیاد قرار دارند و در نهایت مقا...

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