A database of water and heat observations over grassland in the north-east of Japan

Wenchao Ma,Jianqing Xu,Yuichi Onda,Jun Asanuma

doi:10.5194/essd-10-2295-2018

Abstract

Abstract. A highly valuable database of long-term hydrometeorological measurements is presented, containing in situ observations for a period of 37 years from a well-maintained grassland in the north-east of Japan. The observations include shortwave radiation, net radiation, air and dew point temperatures at three elevations, soil temperature at four depths, sensible heat flux, soil heat flux, wind speed, relative humidity, air pressure and precipitation. The heights of measurements are 1.6, 12.5 and 29.5 m above ground, with the soil-layer observations at depths of 0.02, 0.1, 0.5 and 1 m. This high-quality database includes four temporal resolutions of 10 s, 0.5 h, 1 h and 24 h, with the hourly data presented here. Monthly and annual statistics are presented at the database web page of the Center for Research in Isotopes and Environmental Dynamics and Prediction of the University of Tsukuba, http://doi.org/10.24575/0001.198108. We validated the data by comparing them with published data from the local meteorological agency in Tateno operated by the Japan Metrological Agency, including the average, maximum and minimum values of air temperature, shortwave radiation, wind speed, relative humidity and precipitation. We have generated a daily downward longwave radiation time series with a method developed by Kondo and Xu (1997) based on the observations from the database. This constructed time series agrees well with observations collected between 2002 and 2006, as evaluated based on the values of the Nash–Sutcliffe efficiency (=0.947) and percent bias (=1.486). For the whole database, annually averaged values show a positive trend in precipitation, air temperature, shortwave radiation, net radiation and sensible heat flux over the past 37 years, with a negative trend detected for wind speed, soil heat flux and soil temperature.

Highlights

In situ observational databases play a dominant role in all research disciplines
A full set of in situ hydrometeorological observations is introduced here from a well-maintained grassland located in the north-east of Japan, which has been continuously operated since 1981 by the Environmental Dynamics & Prediction (EDP) department of the Center for Research in Isotopes and Environmental Dynamics of the University of Tsukuba, Japan
The daily and annual average values were presented, including the daily values of shortwave radiation, average, maximum and minimum air temperatures, wind speed, relative humidity and precipitation, which were compared with data from the local meteorological agency at Tateno for validation of the data quality

Summary

Introduction

In situ observational databases play a dominant role in all research disciplines. In hydrometeorological studies, water and temperature observations from field work are essential for validating differently sourced data (Jackson et al, 2009; Liang et al, 2011; Guillevic et al, 2012), supporting theoretical modeling (Grayson and Blöschl, 2001), estimating the energy budget (Hirschi and Seneviratne, 2017; Makarieva et al, 2018) and recording historical climatic variation (Godsey et al, 2018; Kormos et al, 2018) for different subjects (Qu et al, 2016; Godsey et al, 2018). A full set of in situ hydrometeorological observations is introduced here from a well-maintained grassland located in the north-east of Japan, which has been continuously operated since 1981 by the Environmental Dynamics & Prediction (EDP) department of the Center for Research in Isotopes and Environmental Dynamics of the University of Tsukuba, Japan This observational site has a long history of providing important contributions to multidisciplinary investigations in many aspects of geological, hydrological, biological and meteorological studies, including micrometeorology both within and outside of the plant community as well as investigations into the transportation of turbulence, evapotranspiration, the soil energy budget and groundwater movement (Kawamura, 1991). Ma et al.: A database of water and heat observations over grassland in the north-east of Japan

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