Seasonal Variation and Characterization of the Micrometeorology in Linpan Settlements in the Chengdu Plain, China: Microclimatic Effects of Linpan Size and Tree Distribution

Abstract

Linpan settlements (abbreviated as Linpan) are the most important traditional type of rural settlement in the Chengdu Plain, and they are an important part of the agroforestry ecological system in southwest China. In this study, we measured the micrometeorological parameters (air temperature, solar radiation, relative humidity, and wind speed) in 12 Linpans for two years to determine the seasonal micrometeorology variations; then, we explored the impacts of Linpan size and tree distribution on the Linpan micrometeorology. The results show that the Linpans undergo seasonal cooling (from 0.6 to 1.3°C), humidification (from 0.9% to 4.1%), reduction in solar radiation flux (from 92.1 to 496.0 W/m2), and changes in wind speed (by 0.4 to 0.5 m/s) compared to the surrounding environment. Both solar radiation flux and wind speed showed the following decreasing trend with respect to sampling positions in the Linpan: outside > edge > center. The Linpan size did not affect the solar radiation flux or wind speed over the four seasons. The main factor affecting solar radiation flux and wind speed was the horizontal tree distribution not the Linpan size. However, the Linpan size was significantly correlated with the air temperature in summer and winter. Large Linpans (>5 × 103 m2) showed better ability to control the temperature to within a comfortable range in extremely hot and cold seasons. The Linpan size also showed a negative relationship with the relative humidity, but only in winter. Among the tree distribution patterns, a scattered distribution was optimal to achieve a comfortable micrometeorology over the course of the year. In addition, we suggest some ways to adapt the Linpan micrometeorology, which could be used to protect traditional Linpans, as well as for ecological restoration.

Impacts of Spatial Components on Outdoor Thermal Comfort in Traditional Linpan Settlements

“…Rectangular buildings account for the highest proportion of interior buildings, followed by L-shaped ones ( Figure 7 b). The vegetation distribution pattern is mostly unilateral, followed by scattered, central, and surrounding, as shown in Figure 7 c, as is consistent with the classification of Linpan vegetation by Zong et al [ 15 ]. These statistical results were used in the later simulation experiment design of thermal comfort.…”

“…In terms of Linpan values, the ecological [ 11 , 12 ], cultural [ 2 ], and aesthetic [ 13 ] values of Linpan have been studied by scholars. In terms of microclimate, Liu et al [ 14 ] and Zong et al [ 15 , 16 ] proved that Linpan could adjust outdoor microclimate in both winter and summer by field measurement. Only field measurements were used to study the microclimate of Linpan, and there is no measurement on different types or spatial components of Linpan; thus, this may affect the accuracy of the results.…”

Farmers’ Strategies to Climate Change and Urbanization: Potential of Ecosystem-Based Adaptation in Rural Chengdu, Southwest China

“…An appropriate location of those forests could maximize multiple benefits. In the Chengdu Plain, taking the linpan as an example, the function of regulating micro-climate by trees or bamboo groves around farmers’ settlements, i.e., warming in winter but cooling in summer [ 48 ], has been recognized popularly by both local people and scholars [ 24 ]. These bamboo and trees in the linpan are not only important habitats for birds that could control insects or pests in the surrounding farming fields, but they also provide fuel woods, construction material and even foods directly to local communities [ 26 ].…”

Perception Study of the Conservation and Utilization of Linpan Cultural Landscape Heritage: The Case of Dujiangyan City

“…In the past three decades, with continuous urbanization, cities have gradually expanded and spread to the suburbs and rural areas, resulting in a gradual decline in rural cultural landscapes. The urbanization rate of the Chengdu Plain Economic Zone rose from 34.22% in 2000 to about 58% in 2021 (Sichuan Provincial Bureau of Statistics, 2022), while the number of Linpan settlements decreased from about 150,000 in 2007 (statistical data not available before 2007) to about 110,000 in 2021 (Rong et al, 2021). Linpan's severe hollowing and aging have been accompanied by the encroachment of arable land, destruction of vegetation and water networks, increased vacancy of land and houses, and growing antagonism between urban and rural areas.…”