Based on the daily climate data from 839 meteorological stations covering the 2014–2017 period in the mainland of China, the Universal Thermal Climate Indices (UTCI) were calculated and the UTCI of 247 national 5A tourist attractions in the mainland of China are obtained with ordinary kriging interpolation method. Then, a spatial analysis of all the attractions was carried out based on UTCI. The results showed that the mainland of China’s annual average UTCI is generally distributed as strip-belts along a latitudinal direction and the climate comfort level gradually decreases from south to north. Significant regional differences in climate comfort results are obtained between the southeast coastal areas and the northwest inland. It was found that the number of attractions with the best climate comfort level is relatively high in spring and autumn while it is less in summer and winter. Considering the climate comfort levels, the attractions are grouped into five categories of “comfortable during spring and autumn,” “comfortable during winter,” “comfortable during spring, autumn, and winter,” “comfortable during spring, summer, and autumn,” and “uncomfortable during the four seasons” to carry out the study for determining the most convenient period of the year in terms of climate comfort.
Climate comfort, also known as thermal comfort, usually refers to the meteorological conditions that humans can ensure their normal physiological metabolism to feel comfortable while not needing any adjustment for heat prevention and/or cold protection [
Research on climate comfort has been around for nearly a hundred years. As early as the 1920s, some scholars began to pay attention to climate comfort research and not only proposed but also established a variety of assessment concepts and models. Early research was based on statistical empirical indicators. Houhton FC proposed an equal comfort line including the variables of temperature and humidity, which also pioneered the use of empirical models for the comfort evaluation [
Over the past 20 years, the tourism industry has developed rapidly in China, especially in the mainland of China. Many new tourism resources and tourism destinations are being established due to the great potential for tourism development by keeping in mind that many tourism activities are climate-sensitive or climate-dependent [
The meteorological data from 839 meteorological stations in the mainland of China is provided by China Meteorological Science Data Sharing Network (Figure
Distribution of meteorological stations in the mainland of China.
This study uses a simplified UTCI calculation method, which refers to the temperature that enables the human body to produce the same physiological response as the actual environment in the standard reference conditions. The standard reference conditions for the model include 0.5 m/s wind speed at 10 m, 50% relative humidity, temperature less than 29°C at 2 m, and 20 hPa vapor pressure for temperature higher than 29°C at 2 m as well as the walking speed of 4 km/h for an adult which is equivalent to a metabolic rate of 135 W/m2. The climate comfort level is categorized according to UTCI as provided in Table
UTCI equivalent temperatures in terms of thermal stress and climate comfort level [
Climate comfort level | UTCI (°C) | Stress category |
---|---|---|
Freezing (1) | <−40 | Extreme cold stress |
Chilly (2) | −40∼−27 | Very strong cold stress |
Cold (3) | −27∼−13 | Strong cold stress |
Coolish (4) | −13∼0 | Moderate cold stress |
Cool (5) | 0∼9 | Slight cold stress |
Comfortable (6) | 9∼26 | No thermal stress |
Warm (7) | 26∼32 | Moderate heat stress |
Hot (8) | 32∼38 | Strong heat stress |
Hottish (9) | 38∼46 | Very strong heat stress |
Torrid (10) | >46 | Extreme heat stress |
The calculation of UTCI is implemented by the software BioKlima 2.6. The average radiant instead of temperature, which is required by the calculation of UTCI, is not directly observed so that cloud data, air pressure, and solar elevation angle are used as surrogate variables. Except for the solar elevation angle, other factors are derived by using site observation data. The solar elevation angle, for instance, is obtained by
Ordinary kriging is an estimation technique known as the best linear unbiased estimator which uses the semivariogram method. Its interpolation through variography provides an interpolation estimate using the observed values and their spatial relationships. Ordinary kriging interpolation, which is detailed in the literature [
The UTCI for all 839 meteorological stations is calculated as the first step. Then, spatial interpolation is performed for each cell with 10 km ∗ 10 km grid points over the study area by the ordinary kriging method using ArcGIS software. According to the criteria listed in Table
As shown in Figure
Spatial distribution of annual average climate comfort in the mainland of China.
The annual average climate comfort evaluation results showed that there are 195 attractions with a climate comfort level of 6, which is the optimal level for a human, indicating that the climate is comfortable. This group accounts for 80% of all tourism locations (Table
The number of national 5A tourist attractions with respect to climate comfort levels in the mainland of China (the total number of scenic spots is 247).
Level 3 | Level 4 | Level 5 | Level 6 | Level 7 | |
---|---|---|---|---|---|
Annual | — | 2 | 44 | 195 | 6 |
Spring | — | 6 | 48 | 185 | 7 |
Summer | — | — | 2 | 113 | 132 |
Autumn | — | 1 | 27 | 206 | 13 |
Winter | 13 | 64 | 105 | 61 | 4 |
Note: “—” indicates that there is no national 5A tourist attraction for the corresponding level.
Figure
Spatial distribution of climate comfort levels of national 5A tourist attractions with respect to seasons.
The spatial distribution of the comfortable attractions during spring and autumn is similar. They are mainly concentrated in the areas along the rivers and oceans including Jiangsu, Anhui, Hunan, Hubei, Guizhou, Zhejiang, and Fujian. Due to the influence of monsoon climate and aerosol changes and the significant thermal inertia of oceans and rivers [
The number of attractions with the best climate comfort level of 6 during autumn is the highest and it accounts for 83%. In winter, the number of areas that experience “no thermal stress” in the same category is only 64 and located in the south of the middle and lower reaches of the Yangtze River because of the Siberian high-pressure influence. On the other hand, the number of attractions with the climate comfort level of 5 is the highest (namely, 108) where the climate conditions with moderate cold stress are not suitable for travel.
For an extended study, the seasonal comfort characteristic is classified into five categories of “comfortable during spring and autumn,” “comfortable during winter,” “comfortable during spring, autumn, and winter,” “comfortable during spring, summer, and autumn,” and “uncomfortable during the four seasons (Figure
The number of national 5A tourist attractions with different comfort categories. I: “comfortable during spring and autumn”; II: “comfortable during spring, autumn, and winter”; III: “comfortable during spring, summer, and autumn”; IV: “uncomfortable during the four seasons”; and V: “comfortable during winter.”
The majority (72%) of the attractions with the best climate comfort level of 6 are located in category I (comfortable during spring and autumn) according to Figure
This study is based on daily climate data of meteorological stations in the mainland of China. The density of meteorological stations is gradually decreasing from the southeast coastal areas to the northwest inland areas due to the uneven geographical distribution of the site. For this reason, the accuracy of the climate comfort evaluation results is inevitably affected to some extent. Quite a fair number of national 5A tourist attractions are located in the mountainous and water areas so the impact of altitude and water thermal inertia on climate comfort are represented. On the other hand, it is also necessary to integrate the Digital Elevation Model (DEM) data to improve the accuracy of the climate comfort evaluation [
In addition, climate comfort is not fixed, and there are many influencing factors in the change of climate factors. Not all of the above research can be fully summarized [
The findings in this study are expected to help to optimize the tourism industry and facilitate the development of national 5A tourist attractions in the mainland of China. There are fewer attractions in the northern and southwest of China although these regions have the best climate comfort level during summer. Thus, more high-quality resorts in these regions should be developed to attract tourists. In the southern parts of Hainan Island, for instance, winter resorts should be promoted to attract tourists who pursue comfortable climate conditions during winter.
This research aims to carry out climate comfort evaluation of national 5A tourist attractions in the mainland of China. Our results show that the annual average climate comfort level in the study area is generally distributed in a strip-like spatial pattern along the latitudinal direction while the climate comfort level gradually decreases from south to north. And there are significant regional differences in terms of climate comfort between the southeast coastal areas and the northwest inland.
A similar spatial distribution of climate comfort is obtained for spring and autumn. The overall number of national 5A tourist attractions located in the comfortable climate zone with the climate comfort level of 6 is higher in spring and autumn while it is less in summer and winter. To extend the study, seasonal climate comfort levels are classified into five categories of “comfortable during spring and autumn,” “comfortable during winter,” “comfortable during spring, autumn, and winter,” “comfortable during spring, summer, and autumn,” and “uncomfortable during the four seasons.” The best climate comfort level is obtained to be during “spring and autumn” where the associated attractions are located between the southeast of the line formed by Taihang, Qinling, and Wushan Mountains as well as north of Hainan Island with an elevation below 1000 meters. The attractions with the best climate comfort level during “spring, autumn, and winter” and those during “winter” occurred in the lower-latitude areas of the south of the middle and lower reaches of the Yangtze River. The attractions with the best climate comfort level during “spring, summer, and autumn” are distributed in the central part of China, near the Taihang and Qinling Mountains. Only 7 attractions in the south of Hainan Island are labeled as “uncomfortable during the four seasons.” The best climate comfort level of 6 occurred only in January and December. The results of this study are expected to be helpful for the optimization of the tourism industry and the development of a high-quality tourism destination.
The meteorological data can be obtained from the China Meteorological Data Network.
The authors declare that there are no conflicts of interest regarding the publication of this paper.
This work was supported by the Natural Science Foundation of China (no. 41701323), Hubei Province Natural Science Foundation of China (no. 2019CFB766), and Fundamental Research Funds for the Central Universities (no. CCNU19TS005).