Characteristics of Horizontal Precipitation in Semi-Humid Forestland in Northern China

Jianbo Jia,Wende Yan,Wenna Liu,Xiaoyong Chen

doi:10.3390/w11050975

Abstract

Little information is available on horizontal precipitation in forest land in semi-humid climate regions. In this study, the quantity and duration of horizontal precipitation were investigated using the high precision weighing lysimeter system in the mountainous areas of northern China during the experiment year 2011 and 2012. The purpose of this study was to better understand the formation mechanisms of horizontal precipitation in the semi-humid climate region. The results showed that hourly values of horizontal precipitation distributed between 0 and 0.1 mm, and that the one-night values distributed between 0.2 and 0.4 mm. The number of days with horizontal precipitation accounted for about 45% of the whole year. The average monthly amount of horizontal precipitation was 4.5 mm in the non-growing season, while it was a mere 1.6 mm in the growing season. The total amount of horizontal precipitation in the year was about 33 mm. Horizontal precipitation represented about 4.61% and 4.23% of the annual precipitation in 2011 and 2012. During the non-growing season, water vapor absorbed by the soil was greater than canopy and soil condensation, not only in terms of frequency, but also in the cumulated quantity. On a typical day, the canopy and soil condensation was 0.07 mm, accounting for 31.81% of total quantity of horizontal precipitation (0.22 mm). Air temperature, soil temperature and wind speed were negatively correlated with the quantity and duration of horizontal precipitation. This research could provide information for a better understanding of the ecological significance of horizontal precipitation in the semi-humid climate region in northern China.

Highlights

Horizontal precipitation, such as dew, fog and frost, is water vapor that is suspended over the earth’s near-surface [1]
Since there was little variation of December, 2011; these two months represented the growing and the non-growing seasons, The results showed that the quantity of canopy and soil condensation and water vapor absorbed by soil the leaf area index throughout the year, analyses were carried out for days in June and days in respectively
Horizontal precipitation added, along with rain and snow, to the ecosystem’s water input. These two forms, i.e., water vapor absorbed by the soil and canopy and soil condensation, and horizontal precipitation, changed the water cycle

Summary

Introduction

Horizontal precipitation, such as dew, fog and frost, is water vapor that is suspended over the earth’s near-surface [1]. Horizontal precipitation usually accounts for a small quantity of the total water input in an ecosystem [3]. It has been proven to be an important water source in making up the deficit in precipitation, especially in arid environments [4,5,6,7]. Horizontal precipitation can improve the development of biological soil crusts [8] and microorganisms [9], increase soil moisture, reduce the vegetation surface temperature and transpiration, which has effects on heat preservation for forest canopies [10,11,12]. Horizontal precipitation is an indispensable part of the heat balance, energy balance and water balance in ecosystems

Objectives

Methods

Results

Discussion

Conclusion