Understanding land use volatility and agglomeration in northern Southeast Asia.

Land use change has generally been considered a cause and consequence of environmental change. Here, we interpreted the land cover in northern Southeast Asia (including parts of Myanmar, Thailand, Laos, Vietnam and China) year by year from 2000 to 2018 with the Google Earth Engine (GEE) platform. The results show that the areas of old growth forest, young growth forest and annual crops have changed dramatically in the study area. The average frequency of land use change was determined to be 5.4 times (that is, the land use changed every 3.4 years) by comparing the land use types in each year throughout the entire study period, and the frequency of land use change showed a significant agglomeration effect. In addition, there was a substantial difference between the land use change determined with an annual approach and that determined with the commonly used time-stage approach; time-stage land use change studies may overlook gradual change processes in land use change, which highlights the necessary of determining a suitable time period for studying land use change at the local scale. The results show that understanding land use volatility and agglomeration has become important to deepen the understanding of land use change and to help formulate land use policy.

Hindering the impact of building characteristics on greenbelt cooling effects: A perspective of quantitative simulation with in situ measurements.

The urban environment, linked with human health, is a complex system disturbed by the roughness of the urban surface, unusually marked by buildings and greenbelts. The cooling effect of greenbelts inevitably responds to the distance from their locations to buildings and their characteristics, while the buildings are hardly independent of the greenbelts in terms of heat effects. To determine the role of building and greenbelt characteristics in mitigating heat stress, our study selected 3 greenbelts and 6 buildings in Beijing, China, and classified them into 2 clusters to compare the difference in monitored outdoor air temperatures (ATs) within two different building characteristics - height and length. One-way analysis of variance (ANOVA) and the least significant difference (LSD) were then employed to further test for significant difference. Our study indicates that each of the two characteristics (height and length) can bring about a significant hindering impact on greenbelt cooling effects. A greater building height or length has a greater hindering force to air (heat) flow. Knowing one or more of the characteristics of greenbelts or buildings is very critical to the improvement of the urban heat environment. Our study proposes an effective and practical outcome for facilitating governmental policy-making and planners' actions.