scholarly journals Comments on Huang et al., "Modeling long-term fire impact on ecosystem characteristics and surface energy using a process-based vegetation-fire model SSiB4/TRIFFID-Fire v1.0"

2020 ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 6029-6050
Author(s):  
Huilin Huang ◽  
Yongkang Xue ◽  
Fang Li ◽  
Ye Liu

Abstract. Fire is one of the primary disturbances to the distribution and ecological properties of the world's major biomes and can influence the surface fluxes and climate through vegetation–climate interactions. This study incorporates a fire model of intermediate complexity to a biophysical model with dynamic vegetation, SSiB4/TRIFFID (The Simplified Simple Biosphere Model coupled with the Top-down Representation of Interactive Foliage and Flora Including Dynamics Model). This new model, SSiB4/TRIFFID-Fire, updating fire impact on the terrestrial carbon cycle every 10 d, is then used to simulate the burned area during 1948–2014. The simulated global burned area in 2000–2014 is 471.9 Mha yr−1, close to the estimate of 478.1 Mha yr−1 in Global Fire Emission Database v4s (GFED4s), with a spatial correlation of 0.8. The SSiB4/TRIFFID-Fire reproduces temporal variations of the burned area at monthly to interannual scales. Specifically, it captures the observed decline trend in northern African savanna fire and accurately simulates the fire seasonality in most major fire regions. The simulated fire carbon emission is 2.19 Pg yr−1, slightly higher than the GFED4s (2.07 Pg yr−1). The SSiB4/TRIFFID-Fire is applied to assess the long-term fire impact on ecosystem characteristics and surface energy budget by comparing model runs with and without fire (FIRE-ON minus FIRE-OFF). The FIRE-ON simulation reduces tree cover over 4.5 % of the global land surface, accompanied by a decrease in leaf area index and vegetation height by 0.10 m2 m−2 and 1.24 m, respectively. The surface albedo and sensible heat are reduced throughout the year, while latent heat flux decreases in the fire season but increases in the rainy season. Fire results in an increase in surface temperature over most fire regions.


2020 ◽  
Author(s):  
Huilin Huang ◽  
Yongkang Xue ◽  
Fang Li ◽  
Ye Liu

Abstract. Fire is one of the primary disturbances to the distribution and ecological properties of the world’s major biomes and can influence the surface fluxes and climate through vegetation-climate interactions. This study incorporates a fire model of intermediate complexity to a biophysical model with dynamic vegetation, SSiB4/TRIFFID (The Simplified Simple Biosphere Model coupled with the Top-down Representation of Interactive Foliage and Flora Including Dynamics Model). This new model, SSiB4/TRIFFID-Fire, updating fire impact on the terrestrial carbon cycle every 10 days, is then used to simulate the burned area during 1948–2014. The simulated global burned area in 2000–2014 is 471.9 Mha yr−1, close to the estimate, 478.1 Mha yr−1, in Global Fire Emission Database v4s (GFED4s) with a spatial correlation of 0.8. The SSiB4/TRIFFID-Fire reproduces temporal variations of the burned area at monthly to interannual scales. Specifically, it captures the observed decline trend in northern African savanna fire and accurately simulates the fire seasonality in most major fire regions. The simulated fire carbon emission is 2.19 Pg yr−1, slightly higher than the GFED4s (2.07 Pg yr−1). The SSiB4/TRIFFID-Fire is applied to assess long-term fire impact on ecosystem characteristics and surface energy budget by comparing model runs with and without fire (FIRE-ON minus FIRE-OFF). The FIRE-ON simulation reduces tree cover over 6.14 % of the global land surface, accompanied by a decrease in leaf area index and vegetation height by 0.13 m2 m−2 and 1.27 m, respectively. The surface albedo and sensible heat are reduced throughout the year, while latent heat flux decreases in the fire season but increases in the rainy season. Fire results in an increase in surface temperature over most fire regions.


2007 ◽  
Vol 20 (17) ◽  
pp. 4476-4485 ◽  
Author(s):  
Jeffrey C. Rogers ◽  
Sheng-Hung Wang ◽  
Jill S. M. Coleman

Abstract A 124 (1882–2005) summer record of total surface energy content consisting of time series of surface equivalent temperature (TE) and its components T (mean air temperature) and Lq/cp (moist enthalpy, denoted Lq) is developed, quality controlled, and analyzed for Columbus, Ohio, where long records of monthly dewpoint temperature are available. The analysis shows that the highest TE occurs during the summer of 1995 when both T and Lq were very high, associated with a severe midwestern heat wave. That year contrasts with the hot summers of 1930–36, when Lq and TE had relatively low or negative anomalies (low humidity) compared to those of T. Following the 1930–36 summers, T and Lq departures are much more typically the same sign in individual summers, and the two parameters develop a statistically significant high positive correlation into the twenty-first century. Mean T and Lq departures from the long-term normal have opposite signs, however, when summers are stratified either by seasonal total rainfall amounts or by the Palmer drought severity soil moisture index. Normalized trends of T, Lq, and TE are downward from 1940 to 1964 with those of TE exceeding T. Since 1965, however, significant positive T trends slightly exceed TE in magnitude and those of dewpoint temperature and Lq are comparatively lower. A highly significant upward trend in minimum temperatures especially dominates the T variability, creating a significant downward trend in the temperature range that dominates recent summer climate variability more than moisture trends. Regional moisture flux variations are largest away from Columbus, over the upper Midwest and western Atlantic Ocean, during its seasonal extremes in total surface energy.


2021 ◽  
Vol 14 (12) ◽  
pp. 7639-7657
Author(s):  
Huilin Huang ◽  
Yongkang Xue ◽  
Ye Liu ◽  
Fang Li ◽  
Gregory S. Okin

Abstract. Fire causes abrupt changes in vegetation properties and modifies flux exchanges between land and atmosphere at subseasonal to seasonal scales. Yet these short-term fire effects on vegetation dynamics and surface energy balance have not been comprehensively investigated in the fire-coupled vegetation model. This study applies the SSiB4/TRIFFID-Fire (the Simplified Simple Biosphere Model coupled with the Top-down Representation of Interactive Foliage and Flora Including Dynamics with fire) model to study the short-term fire impact in southern Africa. Specifically, we aim to quantify how large impacts fire exerts on surface energy through disturbances on vegetation dynamics, how fire effects evolve during the fire season and the subsequent rainy season, and how surface-darkening effects play a role besides the vegetation change effects. We find fire causes an annual average reduction in grass cover by 4 %–8 % for widespread areas between 5–20∘ S and a tree cover reduction by 1 % at the southern periphery of tropical rainforests. The regional fire effects accumulate during June–October and peak in November, the beginning of the rainy season. After the fire season ends, the grass cover quickly returns to unburned conditions, while the tree fraction hardly recovers in one rainy season. The vegetation removal by fire has reduced the leaf area index (LAI) and gross primary productivity (GPP) by 3 %–5 % and 5 %–7 % annually. The exposure of bare soil enhances surface albedo and therefore decreases the absorption of shortwave radiation. Annual mean sensible heat has dropped by 1.4 W m−2, while the latent heat reduction is small (0.1 W m−2) due to the compensating effects between canopy transpiration and soil evaporation. Surface temperature is increased by as much as 0.33 K due to the decrease of sensible heat fluxes, and the warming would be enhanced when the surface-darkening effect is incorporated. Our results suggest that fire effects in grass-dominant areas diminish within 1 year due to the high resilience of grasses after fire. Yet fire effects in the periphery of tropical forests are irreversible within one growing season and can cause large-scale deforestation if accumulated for hundreds of years.


2017 ◽  
Vol 93 ◽  
pp. 110-125 ◽  
Author(s):  
Wondimu W. Teka ◽  
Ranjit Kumar Upadhyay ◽  
Argha Mondal

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