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Accueil du site → Doctorat → Allemagne → 2010 → Factors affecting dewfall, its measurement with lysimeters, and its estimation with micrometerological equations

Martin-Luther-Universität Halle-Wittenberg (2010)

Factors affecting dewfall, its measurement with lysimeters, and its estimation with micrometerological equations

Xiao, Huijie

Titre : Factors affecting dewfall, its measurement with lysimeters, and its estimation with micrometerological equations

Auteur : Xiao, Huijie

Université de soutenance : Martin-Luther-Universität Halle-Wittenberg

Grade : Doctor agriculturarum (Dr. agr.) 2010

Introduction
Dew is a form of precipitation, which is usually not explicitly considered in hydrologic studies, because the amounts are small. However, in semiarid and arid regions dewfall can reach or even exceed all other forms of precipitation for extended periods or indeed a whole year. Even in humid regions it can be the biggest type of precipitation over shorter periods such as a week or a month, although dewfall normally contributes only a small percentage to the total annual precipitation. There is ample evidence that even small amounts of dewfall can be beneficial to plants, not only in arid and semiarid, but also in humid regions. For these reasons it is worth to have a closer looks at some aspects related to dewfall. The specific objectives of this thesis are : - to identify the meteorological factors affecting dew formation and to quantify their effect, - to examine the weighing precision of the type of lysimeter used later in this study to asses its suitability for dew studies, - to quantify the amount of dew precipitated on various types of vegetation in northern Germany during a night and during the course of a year using lysimeters, - to assess different methods to compute dewfall, and - to compare dewfall measured with lysimeters and dewfall computed with the Bowen ratio energy balance and the Penman-Monteith equation.

Présentation

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Page publiée le 23 mai 2021