TY - JOUR
T1 - The Analytical Objective Hysteresis Model (AnOHM v1.0)
T2 - Methodology to determine bulk storage heat flux coefficients
AU - Sun, Ting
AU - Wang, Zhihua
AU - Oechel, Walter C.
AU - Grimmond, Sue
N1 - Funding Information:
Met Office/Newton Fund CSSP-China (SG), National Science Foundation of China (51679119, TS), and U.S. National Science Foundation (CBET-1435881, ZHW). The authors thank Ivan Au (University of Liverpool) for providing the Subset Simulation package. The authors acknowledge the large number of people who have contributed to the data collection, the agencies that have provided sites and the agencies that funded the research at the individual sites. The US Department of Energy's Office of Science funded AmeriFlux data (ameriflux-data.lbl.gov) are from US-Wlr (PIs: David Cook and Richard L. Coulter), CA-NS5 (PI: Mike Goulden), US-SRM (PI: Russell Scott) and US-SO4 (PI: Walt Oechel, funded by San Diego State University and SDSU Field Stations Program). The London data are supported by NERC ClearfLo (NE/H003231/1), NERC/Belmont TRUC (NE/L008971/1), EUf7 BRIDGE (211345), H2020 UrbanFluxes (637519), King's College London and University of Reading. In particular, the authors thank Simone Kotthaus (University of Reading) for her detailed preparation of the UK-Ldn site data. For access to the UK-Ldn site data, please contact c.s.grimmond@reading.ac.uk.
Publisher Copyright:
© Author(s) 2017.
PY - 2017/7/27
Y1 - 2017/7/27
N2 - The net storage heat flux (ΔQS) is important in the urban surface energy balance (SEB) but its determination remains a significant challenge. The hysteresis pattern of the diurnal relation between the ΔQS and net all-wave radiation (Q∗) has been captured in the Objective Hysteresis Model (OHM) parameterization of ΔQS. Although successfully used in urban areas, the limited availability of coefficients for OHM hampers its application. To facilitate use, and enhance physical interpretations of the OHM coefficients, an analytical solution of the one-dimensional advection-diffusion equation of coupled heat and liquid water transport in conjunction with the SEB is conducted, allowing development of AnOHM (Analytical Objective Hysteresis Model). A sensitivity test of AnOHM to surface properties and hydrometeorological forcing is presented using a stochastic approach (subset simulation). The sensitivity test suggests that the albedo, Bowen ratio and bulk transfer coefficient, solar radiation and wind speed are most critical. AnOHM, driven by local meteorological conditions at five sites with different land use, is shown to simulate the ΔQS flux well (RMSE values of ∼30Wm-2). The intra-annual dynamics of OHM coefficients are explored. AnOHM offers significant potential to enhance modelling of the surface energy balance over a wider range of conditions and land covers.
AB - The net storage heat flux (ΔQS) is important in the urban surface energy balance (SEB) but its determination remains a significant challenge. The hysteresis pattern of the diurnal relation between the ΔQS and net all-wave radiation (Q∗) has been captured in the Objective Hysteresis Model (OHM) parameterization of ΔQS. Although successfully used in urban areas, the limited availability of coefficients for OHM hampers its application. To facilitate use, and enhance physical interpretations of the OHM coefficients, an analytical solution of the one-dimensional advection-diffusion equation of coupled heat and liquid water transport in conjunction with the SEB is conducted, allowing development of AnOHM (Analytical Objective Hysteresis Model). A sensitivity test of AnOHM to surface properties and hydrometeorological forcing is presented using a stochastic approach (subset simulation). The sensitivity test suggests that the albedo, Bowen ratio and bulk transfer coefficient, solar radiation and wind speed are most critical. AnOHM, driven by local meteorological conditions at five sites with different land use, is shown to simulate the ΔQS flux well (RMSE values of ∼30Wm-2). The intra-annual dynamics of OHM coefficients are explored. AnOHM offers significant potential to enhance modelling of the surface energy balance over a wider range of conditions and land covers.
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U2 - 10.5194/gmd-10-2875-2017
DO - 10.5194/gmd-10-2875-2017
M3 - Article
AN - SCOPUS:85026661286
VL - 10
SP - 2875
EP - 2890
JO - Geoscientific Model Development
JF - Geoscientific Model Development
SN - 1991-959X
IS - 7
ER -