دانلود مقاله ترجمه شده تعامل بین خواص سطح خاک و فرسایش آبی – مجله الزویر

فهرست مطالب:

چکیده
۱ مقدمه
۲ جریان سطحی و انتقال رسوب در سطوح زبر
۳ مدل فرسایش استانه ی سطحی
۴ نتیجه گیری

بخشی از ترجمه:

چنین استدلال می شود که اثرات متقابل حین خصوصیات طحی به خصوص میکرو توپوگرافی و سله بندی بر کمیت و الگوی مکانی رواناب سطحی تاثیر می گذارند.این اثرات متقابل در همه ی مقیاس از مقیاس های زبری فردی تا مقیاس های حوزه ای دیه می شود.اگر چه پارامتر سازی زبری می تواند به صورت وابسته به مقیاس و بارندگی باشد اما مفهوم ظرفیت ذخیره ی موثر وی ا استانه ی رواناب در دامنه های مقیاس های مربوطه بسیار مهم است و در بسیاری از موارد به شدت بستگی به خواص سطحی خاک و توزیع ان ها دارد.
تغییرات تصادفی هم در شدت باران و هم در ذخیره و خصوصیات نفوذ بر مقدار و توزیع رواناب تاثیر می گذارد و اثرات متقابل بین این تغییر پذیری ها ایجاد وابستگی های قوی بین اندازه ی یمانگین قطه باران و طول دامنه برای یک طح معین می کنند.همه ی این روابط درونی هنوز به اندازه ی کافی خوب درک نشده اند که ما بتوانیم از ان ها برای ایجاد مدل های مناسب فرسایش و رسوب و چشم انداز استفاده کنیم. همچنین ان ها اصول و قواعد مفهومی مهم را برای تنظیم و واسنجی پلات ها تا مقیاس حوزه ای در اختیار می گذارند و به این ترتیب درک بهتر از نتایج تجربی و کاربرد ان ها در سطوح بزرگ تر حاصل خواهد شد.

بخشی از مقاله انگلیسی:

1. Introduction Soil erosion models commonly include parameters based on fixed soil properties or moisture–tension curves, but rarely take account of the dynamics linking soil and surface properties with water erosion processes, which are relevant at a range of time and space scales. The four sub-systems of Soil, Vegetation, Atmosphere and Surface interact dynamically with one another within each site, and sites are linked by lateral transfers of water, sediment and solutes in a downslope direction Fig. 1 . Ž . Over short within-storm periods, soils properties influence erosion mainly through their hydrology, aggregate stability, and cation dispersion. Over periods of decades, erosion can lead to profile truncation and armouring of the surface, and these changes then influence subsequent rates and patterns of erosion. Over the still longer periods of soil evolution, the balance between mechanical and chemical denudation determines the entire weathering profile and its variation downslope to create hillslope catenas, which in turn also influence the distribution of erosion rates. Similarly, erosion interacts with soil properties at a wide range of spatial scales. Macro-pores and crusting are examples of dominant influences at the finest 10 –10 Ž y3 y1 m scales, and give way in importance to spatial patterning produced by cultivation or . natural vegetation location at moderate 1–10 m scales, to catena differences at the Ž . Ž 2 3 . Ž 4 5 hillslope 10 –10 m scale, to major soil series at the catchment 10 –10 m scale and . Ž 6 8 to climatically based major soil groups at continental 10 –10 m scales. In all cases, . there are also strong links with soil via the vegetation cover, so that the direct importance of the soil is greatest under sparse covers. The direct links with the soil are therefore strongest under arid and semi-arid climates for uncultivated areas. Under conditions of global change, relatively slow changes in soils and erosion rates are giving way to much more rapid modifications under the impact of climate and landuse change. Under these strongly non-equilibrium conditions, many ‘natural’ inter-relationships between the soils and the associated pattern of erosion will be broken down, demanding a more fundamental assessment of cause and effect in highly disturbed systems and making it difficult to use analogue studies with any confidence. On natural semi-arid surfaces, microtopography evolves through sediment transfers and through the dynamics associated with mounds around perennial shrubs, with a time scale of decades to hundreds of years. On cultivated fields, microtopography is created by tillage operations and destroyed by sediment transfers over an annual cycle. These two systems have rather different dynamics but a number of important features in common. This paper explores developments with respect to one set of processes which are believed to be important, and have been relatively neglected—the interactions between overland flow, water erosion and surface microtopography. This theme is being explored through research in a number of related erosion models, which are concerned with the wide range of relevant spatial and temporal scales. Some are primarily related to hydrology, others to soil erosion under global change while others are concerned with the evolution of soils and landforms over geological time spans. These include the MEDALUS and MEDRUSH models Kirkby et al., 1997, 1998 , the Regional Degrada- Ž . tion Index RDI Ž . rCSEP: Kirkby and Cox, 1995 and a number of models for long-term landscape evolution e.g. Kirkby, 1991, 1992, 1994 . Ž . 2. Overland flow and sediment transport on rough surfaces Roughness due to random irregularities on a soil surface is usually well represented as a normal distribution of elevations relative to a mean, and is characterized by its standard deviation, or RMS roughness. There may also be various forms of systematic roughness due to tillage operations or, at a coarser scale, to terracing. Their orientation with respect to the slope direction is vitally important, particularly for long linear features like plough ridges. The scale dependence of roughness is not fully understood, but it is clear that roughness occurs at a number of scales, and natural roughness may well have a fractal or similar structure, with larger RMS roughness as it is measured with a coarser grid of points. At sufficiently coarse scales, roughness of natural surfaces merges into landscape elements such as ephemeral gullies and stream valleys. Cultivated areas also show systematic roughness elements, most strikingly at the scales of plough furrows and terrace systems.

دانلود رایگان مقاله انگلیسی

خرید ترجمه فارسی مقاله با فرمت ورد

خرید نسخه پاورپوینت این مقاله جهت ارائه