Modulation of Land-Use Change Impacts on Temperature Extremes via Land–Atmosphere Coupling over Australia

Abstract

The role of land-atmosphere coupling in modulating the impact of land-use change (LUC) on regional climate extremes remains uncertain. Using the Weather and Research Forecasting Model, this study combines the Global Land-Atmosphere Coupling Experiment with regional LUC to assess the combined impact of land-atmosphere coupling and LUC on simulated temperature extremes. The experiment is applied to an ensemble of planetary boundary layer (PBL) and cumulus parameterizations to determine the sensitivity of the results to model physics. Results show a consistent weakening in the soil moisture-maximum temperature coupling strength with LUC irrespective of the model physics. In contrast, temperature extremes show an asymmetric response to LUC dependent on the choice of PBL scheme, which is linked to differences in the parameterization of vertical transport. This influences convective precipitation, contributing a positive feedback on soil moisture and consequently on the partitioning of the surface turbulent fluxes. The results suggest that the impact of LUC on temperature extremes depends on the land-atmosphere coupling that in turn depends on the choice of PBL. Indeed, the sign of the temperature change in hot extremes resulting from LUC can be changed simply by altering the choice of PBL. The authors also note concerns over the metrics used to measure coupling strength that reflect changes in variance but may not respond to LUC-type perturbations.

Evaluation of the CABLEv2.3.4 Land Surface Model Coupled to NU‐WRFv3.9.1.1 in Simulating Temperature and Precipitation Means and Extremes Over CORDEX AustralAsia Within a WRF Physics Ensemble

“…Offline model spin‐up was carried out over a period of 4 years, starting in August 2004, with the Princeton meteorological forcing at 3‐hourly frequency (Sheffield et al, ), consistent with our previous work using NU‐WRF (Hirsch, Kala, et al, ; Hirsch, Pitman, Seneviratne, et al, ; Hirsch, Pitman, & Kala, ; Hirsch et al, ). We note that while it is theoretically possible to run the offline spin‐up with ERA‐Interim, for consistency with the lateral boundary conditions used during the coupled simulation, 6‐hourly meteorological forcings are not frequent enough for offline simulations, hence our choice of Princeton forcing.…”

“…For coupled regional applications, previous work with WRF‐LIS‐CABLE used an older version of CABLE (version 1.4b), which does not incorporate any of these recent developments. Additionally, these studies only focused on the Austral summer period, as they investigated heat extremes (Hirsch, Kala, et al, ; Hirsch, Pitman, Seneviratne, et al, ; Hirsch, Pitman, & Kala, ; Hirsch et al, ). Given the WRF model is well documented to be highly sensitive to the choice of physical parameterizations (e.g., Evans et al, ; Kala, De Kauwe, et al, ), and previous work with WRF‐LIS‐CABLE has been limited to four different WRF configurations only, a comprehensive sensitivity analysis of the WRF model to different parameterization options for Australia is limited.…”

The Land Use Model Intercomparison Project (LUMIP) contribution to CMIP6: rationale and experimental design

“…In a single model study of Amazonian deforestation, Lorenz and Pitman (2014) find that this is indeed the case -small amounts of deforestation in a part of the Amazon domain where the model simulates strong land-atmosphere coupling has a larger impact on temperature than extensive deforestation in a weakly coupled region. Similarly, Hirsch et al (2015) show that different planetary boundary layer schemes, which lead to different land-atmosphere coupling strengths, can modulate the impact of land-use change on regional climate extremes. LUMIP will collaborate with LS3MIP to systematically investigate the inter-relationships between landatmosphere coupling strength, which can be diagnosed in any coupled simulation (e.g., Dirmeyer et al, 2014;Seneviratne et al, 2010), and LULCC impacts on climate, and establish to what extent differences in land-atmosphere coupling strength across models (Koster et al, 2004) contribute to differences in modeled LULCC impacts.…”

Biogeophysical Impacts of Land‐Use Change on Climate Extremes in Low‐Emission Scenarios: Results From HAPPI‐Land

“…The impacts of land use and land management for food production and forestry have been shown to have considerable influence on local and regional climate, particularly for climate extremes (Avila et al, ; Davin et al, ; de Noblet‐Ducourdé et al, 2012; Hirsch et al, , ; Lejeune et al, ; Luyssaert et al, ; Pielke et al, ; Pitman et al, , ). With the recent commitment to limit global warming to well below 2°C (United Nations Framework Convention on Climate Change [UNFCCC], ) and to pursue efforts to stabilize at 1.5°C, emission reductions need to be ambitious and could involve major land‐based mitigation measures (Popp et al, ; van Vuuren et al, ).…”