Advances in Land Surface Modelling

Abstract

Land surface models have an increasing scope. Initially designed to capture the feedbacks between the land and the atmosphere as part of weather and climate prediction, they are now used as a critical tool in the urgent need to inform policy about land-use and water-use management in a world that is changing physically and economically. This paper outlines the way that models have evolved through this change of purpose and what might the future hold. It highlights the importance of distinguishing between advances in the science within the modelling components, with the advances of how to represent their interaction. This latter aspect of modelling is often overlooked but will increasingly manifest as an issue as the complexity of the system, the time and space scales of the system being modelled increase. These increases are due to technology, data availability and the urgency and range of the problems being studied.

Land Use Effects on Climate: Current State, Recent Progress, and Emerging Topics

“…Thereof, the by far largest source was livestock, particularly cattle in intensive agricultural systems of wealthier and emerging economies [125], with estimated emissions from enteric fermentation and manure management (the latter causing CH 4 fluxes mainly under anaerobic conditions) of 111 (106)(107)(108)(109)(110)(111)(112)(113)(114)(115)(116) Tg CH 4 year −1 [12], which is in agreement with the recent IPCC Tier 2 estimate of 99 ± 12 Tg CH 4 year −1 for 2012 [128]. Rice cultivation contributes 30 (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38) Tg CH 4 year −1 globally, mainly due to periodic flooding and aeration of paddy rice fields and fertilization [12]. Asia contributes 30-50% to global CH 4 emissions from rice cultivation [129], but over recent decades most inventories show a decreasing trend due to reduced areal extent, changed management, and northward shift of rice cultivation [12].…”

“…Basic LULCC activities were already implemented in early-generation DGVMs and have been extended steadily [2]. The improvement of LULCC representation went in parallel with relevant improvements in general land surface process representation [27]. Recent progress includes processes such as grazing, irrigation, tillage, or plant species selection (see Fig.…”

“…The strength of biogeophysical LULCC effects on regional and global climate is still a matter of debate. Despite the identification of a large spread among models in LUCID [148] and the following substantial progress in the representation of terrestrial processes and LULCC practices in models [2,27], more recent model intercomparison studies still find that not all models agree on the sign of global and regional temperature changes for historical [149,150], future [37], and idealized [151] LULCC scenarios. Some major differences between model studies with different setups and between models and observations, however, could be attributed to different scopes of the studies (see Spotlight: Can We Reconcile the Seemingly Contradicting Results of Models and Observations Concerning the Cooling Effect of High-Latitude Deforestation?).…”

Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)

“…In particular, the sub-grid processes already described can 70 result in these wetter areas also being warmer, meaning that the modelled methane flux may be too low. The resolution of these sub-grid processes and the resulting heterogeneity is similarly a key challenge for other global models used for future climate projections, and needs to be addressed in order to avoid underestimating the permafrost carbon feedback (Bridgham et al, 2013;Blyth et al, 2021;Aas et al, 2019). This study therefore aims to investigate the hypothesis that explicitly modelling microtopography is essential to accurately modelling the ground moisture, temperature and hence methane emissions of a 75 permafrost landscape.…”

Improved Streamflow Calibration of a Land Surface Model by the Choice of Objective Functions—A Case Study of the Nakdong River Watershed in the Korean Peninsula

“…Water 2021, 13, 1709 2 of 16 For analysis of climate-induced streamflow extremes and water balance changes, it is necessary to simulate the spatial and temporal variability in the surface and subsurface runoff using the distributed hydrological modelling that can reflect topographic features as well as respond to meteorological forcings from the coupled or uncoupled climate application system. As for the context of the perspectives and advances in the Land Surface Models (LSMs) [10,11], the LSMs can be a useful tool to simulate the partitioning of precipitation into evapotranspiration and runoff by integrating meteorological factors and the physical geology of the land [12][13][14][15]. As the LSMs coupled to global or regional climate models simulate the water and energy exchanges between the land surface and the atmosphere, robust LSMs are required to provide a comprehensive assessment of hydrological responses to climate change at both regional and global scales [16,17].…”