A measurement, quantitative identification and estimation method(QINRW) of non-rainfall water component by lysimeter

Qiang Zhang,Sheng Wang,Ping Yue,Runyuan Wang

doi:10.1016/j.mex.2019.11.012

Abstract

Non-rainfall water (NRW) has an important impact on the ecosystem, especially in arid and semi-arid areas. It is also an important component in the surface water cycle. Currently, there is not any instrument that can directly measure NRW and it can only be estimated by observation data. Presently, there is no standard method available to estimate each constituents of NRW. With some research not distinguishing each component of NRW, this inaccurate methodology will consequently lead to a greater scope for statistical error. Naturally, this compounds the difficulty in evaluating the role of NRW on the ecosystem and land surface water cycle. Therefore, this paper proposes a new methodology for separating NRW components, which is called QINRW(A Quantitative Identification method for NRW). Based on lysimeter data and combined with meteorological data, this method distinguishes the physical properties of each component of NRW. Consequently, the amount of NRW can be obtained. It is also suitable for microlysimeter data to be applied in QINRW.The advantages of QINRW are three points:•It is more accurate for excluding the precipitation and dry deposition information from lysimeter data, which was not mentioned in previous studies;•It can obtain each component of NRW;•The identification process is more rigorous and clear in theory so far.

Highlights

Land surface water process refers to those processes including transport, exchange and phase transformation of water vapor occurring between the atmosphere and land surface
Non-rainfall water (NRW) is an important component of the Land surface water balance; It includes of three soil components: soil distilled water,vascular water and guttation
If precipitation occurs during the above observation period, it is assumed that the added value of lysimeter data is precipitation, not NRW; if no precipitation occurs, it is assumed that the added value may be NRW

Summary

Introduction

Non-rainfall water (NRW) refers to land surface liquid water, excluding natural precipitation and artificial irrigation [1,2]. There is no direct observation instrument available to measure the atmosphere components of NRW, which can only be estimated indirectly from observation data; in the current study, NRW only refers to fog, dew and WVA [3,9]. The predominant instruments employed for observing NRW include a Hiltner Dew Balance [10,11], a leaf wetness sensor [12] and a microlysimeter or lysimeter [3,9].

Results

Conclusion