# Review of Land Surface Albedo: Variance Characteristics, Climate Effect and Management Strategy
## 4 Climate Feedback and Management Strategy for Surface Albedo
### Monitoring Short-to-Long-Term Albedo Change and Climate Effects
#### 4.1.3 Application in Ecology and Climate Simulations
High-albedo materials may be used widely in urban areas, particularly in warm and hot climates, and a modelling study shows their ability to achieve higher air quality with a net effect of reducing ozone concentrations [207]. A three-dimensional numerical model (the Model for Urban Surface Temperature (MUST)) was used to investigate the impact of urban geometry on average urban albedo and street surface temperature, where the average sky-view factor plays an essential role [141]. A numerical model was used to evaluate the impact of street canyons on subsequent pedestrian heat stress using the mean radiant temperature [141], and the optimal combinations of urban albedo and green covering were determined to improve the urban microclimate (e.g., outdoor air temperature and mean radiant temperature) based on environmental analysis model ENVI-met [208; 209]. Based on a WRF model, high-albedo urban materials can mitigate the UHI effect but worsen the outdoor thermal sensation [210]. In addition, large-scale climate change has been associated with surface albedo based on a series of circulation and forecast models in global climate forecasts [211; 212] and regional weather forecasts [213]. Near real-time surface albedo has been used to improve the Noah land surface model [212]. Although carbon sequestration or modern biomass plantations can mitigate the greenhouse climate by 2100 according to integrated assessment model IMAGE 2.2, the subsequent reduction in surface albedo can increase surface temperature and offset climate contributions [214]. According to simulations by IPCC AR5 Coupled Model Intercomparison Project Phase 5 (CMIP5) for the past 150 years using the climate model and emissions from preindustrial times to the present day [73], aerosols show a small positive radiative forcing induced by their surface albedos (+0.016 W/m\({}^{2}\)) and would lead to ten times larger positive TOA radiative forcing, although the overall effect on solar radiation and clouds is most certainly negative (\(-\)0.6 W/m\({}^{2}\)). Emergent constraints are proposed to reduce intermodel variability in projections of climate change based on CMIP6 [215], which occurs each year as snow and sea ice retreat from their seasonal maxima and which is strongly correlated with future surface albedo feedback in modern-day analogues. Based on general circulation model ECHAM5-JSBACH, the dynamics of vegetation albedo and background soil albedo have shown an improvement in the frequency and persistence of precipitation anomalies in the Sahel region, respectively [216]. In addition, cloud-compensated hemispheric asymmetries in clear-sky albedo show that hemispheric albedo asymmetries have induced a series of climate changes by coupling ECHAM6 to a slab ocean model [217]. Eleven Earth system models are used to investigate climate effects by maintaining net TOA radiation balance with an imposed forcing of an abrupt quadrupling of the CO\({}_{2}\) concentration and an instantaneous increase in ocean albedo, and opposing trends are observed for air temperature over the land surface (increase by 1.14 \({}^{\circ}\)C on average) and most of the ocean (decrease) [19]. These results reinforce previous findings that keeping TOA net radiation constant is not sufficient for preventing changes in global mean temperature. In particular, surface albedo is also necessary to model climate variances in past periods, such as the impact of surface albedo on climate variations in the Phanerozoic [218], Sahel/Sahara precipitation in the mid-Holocene [219], the \"Snowball Earth\" hypothesis of the Neoproterozoic glacial episodes [220], the early Archean climate [221] and the Pliocene Arctic climate [222].