Representing the atmospheric boundary layer in climate models of intermediate complexity

Ronda, R.J.; Haarsma, Reindert J.; Holtslag, A.A.M.

doi:10.1007/s00382-003-0338-0

Cited by 4 publications

(5 citation statements)

References 32 publications

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“…The assumption that C h = C e was adopted in this study, which denotes the equality of the transfer coefficient for heat and water vapour because of a high correlation between the temperature and specific humidity of air originating at the evaporating surface (Charnock and Ellison, 1959; Högström, 1967; Swinbank and Dyer, 1967). The approximation has been commonly used by most numerical modellers (e.g., Chen et al ., 1997; Ronda et al ., 2003; Trier et al ., 2011; Huang et al ., 2016), and has also been directly applied in the theoretical estimation of LH (e.g., Park et al ., 2010). However, it should be noted that the validity of the approximation for the boundary conditions over land would be more favourable than over water (Paulson, 1969).…”

Section: Discussionmentioning

confidence: 99%

Assessment of surface exchange coefficients in the Noah‐MP land surface model for different land‐cover types in China

Xia

Chen

et al. 2021

Intl Journal of Climatology

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The parameterization of surface exchange coefficients (Ch) representing land–atmosphere coupling strength plays a key role in land surface modelling. Previous studies have found that land–atmosphere coupling in land surface models (LSMs) is largely overestimated, which affects the predictability of weather and climate evolution. To improve the representation of land–atmosphere interactions in LSMs, this study investigated the impact of dynamic canopy‐height‐dependent coupling strength in an offline Noah LSM with multi‐parameterization options (Noah‐MP) when applied to China. Comparison with the default Noah‐MP LSM showed that the dynamic scheme significantly improved the Ch calculations and realistically reduced the biases of simulated surface energy and water components against observations. It is noteworthy that the improvements brought about by the dynamic scheme differed across land‐cover types. The scheme was superior in reproducing the observed Ch as well as surface energy and water variables for short vegetation (grass, crops, and shrubs), whereas the improvement for tall canopy vegetation (forest) was not significant although the estimations were reasonable. The improved version benefits from the treatment of the roughness length for heat. Further, the scheme can better reproduce the observed surface thermal components, while the improvement in hydraulic variables (such as soil moisture) remains limited. Overall, the dynamic coupling scheme markedly affects the simulation of land–atmosphere interactions, and altering the dynamics of surface coupling has the potential to improve the representation of land–atmosphere interactions and, thus, the further development of LSM.

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Section: Discussionmentioning

confidence: 99%

Assessment of surface exchange coefficients in the Noah‐MP land surface model for different land‐cover types in China

Xia

Chen

et al. 2021

Intl Journal of Climatology

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“…For our experiments and the coupling to LPJmL, we extended SPEEDY by a diurnal cycle (instead of an everlasting half-light), a dynamic boundary layer over land, based on Ronda et al (2003), and an exchange of data with LPJmL at every 40-min time step (see Section 2.3). A detailed description of the extentions made to SPEEDY can be found in the Supporting Information 1.…”

Section: Methodsmentioning

confidence: 99%

Assessing 20th century climate–vegetation feedbacks of land‐use change and natural vegetation dynamics in a fully coupled vegetation–climate model

Strengers

Müller

Schaeffer

et al. 2010

Intl Journal of Climatology

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This study describes the coupling of the dynamic global vegetation model (DGVM), Lund-Potsdam-Jena Model for managed land (LPJmL), with the general circulation model (GCM), Simplified Parameterizations primitivE Equation DYnamics model (SPEEDY), to study the feedbacks between land-use change and natural vegetation dynamics and climate during the 20th century. We show that anthropogenic land-use change had a stronger effect on climate than the natural vegetation's response to climate change (e.g. boreal greening). Changes in surface albedo are an important driver of the climate's response; but, especially in the (sub)tropics, changes in evapotranspiration and the corresponding changes in latent heat flux and cloud formation can be of equal importance in the opposite direction. Our study emphasizes that implementing dynamic vegetation into climate models is essential, especially at regional scales: the dynamic response of natural vegetation significantly alters the climate change that is driven by increased atmospheric greenhouse gas concentrations and anthropogenic land-use change.

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“…The modeling was improved by using the abovementioned Penman-Monteith parameterization for evapotranspiration (Sect. 2.3.2) and by increasing the tropical rooting depths and, hence, the soil water access of the trees (Sakschewski et al, 2020). Global biomass patterns are now also comparable with the standalone LPJmL5 version (Fig.…”

Section: Challenges Of Coupling Lpjml5 Into Cm2mcmentioning

confidence: 58%

“…The key advantages of CM2Mc-LPJmL are the relatively fast and computational inexpensive atmosphere-ocean general circulation model (due to its relatively low spatial resolution) and the ability to investigate detailed feedbacks of the biosphere using the state-of-the-art DGVM LPJmL5. While LPJmL5 is constantly improved, recent new features such as a process-based nitrogen cycle (Von Bloh et al, 2018), a tillage system for land use (Lutz et al, 2019) or variable root growth (Sakschewski et al, 2020) can be integrated into the modeling framework consecutively and tested in the Earth system model. The coupled model also remains flexible for new model compartments such as a new atmosphere or a new ocean model, which are compatible with FMS.…”

Section: Discussionmentioning

confidence: 99%

CM2Mc-LPJmL v1.0: biophysical coupling of a process-based dynamic vegetation model with managed land to a general circulation model

et al. 2021

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Abstract. The terrestrial biosphere is exposed to land-use and climate change, which not only affects vegetation dynamics but also changes land–atmosphere feedbacks. Specifically, changes in land cover affect biophysical feedbacks of water and energy, thereby contributing to climate change. In this study, we couple the well-established and comprehensively validated dynamic global vegetation model LPJmL5 (Lund–Potsdam–Jena managed Land) to the coupled climate model CM2Mc, the latter of which is based on the atmosphere model AM2 and the ocean model MOM5 (Modular Ocean Model 5), and name it CM2Mc-LPJmL. In CM2Mc, we replace the simple land-surface model LaD (Land Dynamics; where vegetation is static and prescribed) with LPJmL5, and we fully couple the water and energy cycles using the Geophysical Fluid Dynamics Laboratory (GFDL) Flexible Modeling System (FMS). Several improvements to LPJmL5 were implemented to allow a fully functional biophysical coupling. These include a sub-daily cycle for calculating energy and water fluxes, conductance of the soil evaporation and plant interception, canopy-layer humidity, and the surface energy balance in order to calculate the surface and canopy-layer temperature within LPJmL5. Exchanging LaD with LPJmL5 and, therefore, switching from a static and prescribed vegetation to a dynamic vegetation allows us to model important biospheric processes, including fire, mortality, permafrost, hydrological cycling and the impacts of managed land (crop growth and irrigation). Our results show that CM2Mc-LPJmL has similar temperature and precipitation biases to the original CM2Mc model with LaD. The performance of LPJmL5 in the coupled system compared to Earth observation data and to LPJmL offline simulation results is within acceptable error margins. The historical global mean temperature evolution of our model setup is within the range of CMIP5 (Coupled Model Intercomparison Project Phase 5) models. The comparison of model runs with and without land-use change shows a partially warmer and drier climate state across the global land surface. CM2Mc-LPJmL opens new opportunities to investigate important biophysical vegetation–climate feedbacks with a state-of-the-art and process-based dynamic vegetation model.

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Representing the atmospheric boundary layer in climate models of intermediate complexity

Cited by 4 publications

References 32 publications

Assessment of surface exchange coefficients in the Noah‐MP land surface model for different land‐cover types in China

Assessment of surface exchange coefficients in the Noah‐MP land surface model for different land‐cover types in China

Assessing 20th century climate–vegetation feedbacks of land‐use change and natural vegetation dynamics in a fully coupled vegetation–climate model

CM2Mc-LPJmL v1.0: biophysical coupling of a process-based dynamic vegetation model with managed land to a general circulation model

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