The response and feedback of land surface processes to climate change constitute a research priority in the field of geosciences. Previous studies have focused on the impacts of global climate change on land surface processes; however, the feedback of land surface processes to climate change remains unknown. It has become increasingly meaningful under the framework of Earth system science to understand systematically the relationships between agricultural phenology dynamics and biophysical processes, as well as their feedback to climate change. This study summarized research progress in this field, including agricultural phenology change, parameterization of phenology dynamics in land surface process models, and the influence of agricultural phenology dynamics on biophysical processes, as well as its feedback to climate. The results showed that the agricultural phenophase, represented by paramount phenological phases such as sowing, flowering, and maturity, has shifted significantly because of the impacts of climate change and agronomic management. Digital expressions of dynamic land surface processes, as well as biophysical and atmospheric processes, have been improved by coupling phenology dynamics in land surface models. Agricultural phenology dynamics influence net radiation, latent heat, sensible heat, the albedo, temperature, precipitation, and circulation, thus, play an important role in surface energy partitioning and climate feedback. Considering the importance of agricultural phenology dynamics in land surface biophysical processes and climate feedback, the following research priorities have been identified: (1) interactions between climate change and land surface phenology dynamics, (2) relationships between agricultural phenology dynamics and different land surface reflectivity spectra, (3) contributions of changes in crop physiological characteristics to land surface biophysical processes, and (4) regional differences of climate feedback from phenology dynamics in different climatic zones. This review will be helpful in accelerating the understanding of the role of agricultural phenology dynamics in land surface processes and climate feedback.
Based on the daily average temperature of 48 meteorological stations in Chinese oases of the distribution area of Populus euphratica, we analyzed spatio-temporal response of the onset and upset date of P. euphratica, and the dates of growing season to climate change, with the aid of methods including a multi-year trend line, Mann-Kendall mutation test, IDW under the ArcGIS software, Morlet wavelet power spectrum, and correlation analysis. The results indicate that in the past 56 years, the onset date of the growing season has advanced and the upset date has postponed; the dates of the growing period have gradually prolonged, with the trend rates being -1.34 d/10a, 1.33 d/10a, 2.66 d/10a (α≥ 0.001), respectively. The spatial difference is extremely significant, which presents the following law: from the southwest to the northeast in Chinese oases, the onset date has postponed, the upset date advanced, and the growing period shortened. The mutation point of the onset and upset dates and growing period is observed in 2001, 1989, and 1996, respectively, and the upset date is more sensitive to climate warming. The cycles of the growing season of P. euphratica are 3.56-7.14 years, which is consistent with the cycle of the El Nino event, and the onset date cycles of 3.56 years and 4.28 years are consistent with that of atmospheric circulation. Cause analysis shows that the Asian polar vortex area index, the Qinghai-Tibet Plateau index, Westerly Circulation index, and the carbon dioxide emissions are the main reasons for the change of the growing season for P. euphratica, and consistent with the results of the periodic analysis. In addition, the influence of latitude in the growing season is significantly larger than that of altitude, while the onset date is more significant than the upset date in terms of latitude and altitude. Additionally, the onset and upset dates and growing period are significantly correlated with the average temperature of corresponding month, with the correlation coefficients being -0.875, 0.770, and 0.897, respectively (α≥ 0.001). Specifically, if the March average temperature increases by 1 ℃, the onset date will occur about 2.21 days earlier; if the October average temperature increases by 1 ℃, the upset date will delay for 2.76 days; if the average temperature of March to October increases by 1 ℃, the growing period will prolong for 7.78 days. This indicates that the change of P. euphratica in the growing season has a sensitive response to regional warming. This study is of great theoretical significance in understanding the response of Chinese vegetation to climate warming and ecological restoration.
Based on the daily minimum temperature data from 52 observational stations in Liaoning Province and the NCEP/NCAR reanalysis data from 1975 to 2015, with composite analysis and correlation analysis, the spatial and temporal features of the winter minimum temperature in Liaoning and North Pacific storm track are analyzed, and the North Pacific storm track anomaly and its relationship with winter minimum temperature are studied. Some conclusions are drawn as follows. The winter minimum temperature in Liaoning had an obvious abrupt change around 1986, then the temperature continued to rise. The North Pacific storm track and the winter minimum temperature had synchronous consistent variation. In the years when North Pacific storm track was stronger, the winter minimum temperature was affected by the southwestern flow; at the same time, the Aleutian Low and Siberian High were at lower level, and the East Asia Trough weakened as it moved to north, the East Asian westerly jet stream at 500 hPa also moved to north. All these led to the weaker East Asian winter monsoon circulation, which was not conducive to the southward movement of cold air, leading to a higher winter temperature in Liaoning. In the years when North Pacific storm track was weaker, lower air temperature was observed in Liaoning. The main reason for the change of relationship with North Pacific storm track intensity and winter minimum temperature is anomalous change of atmospheric circulation at middle and high latitudes.
Glacial lakes not only provide the important refresh water resources in alpine region, but also act as a trigger of many glacial hazards such as glacial lake outburst flood (GLOF) and debris flow. Hence glacial lakes play an important role in the research related with cryosphere, climate change and alpine hazards. In this paper, the issues of glacial lakes were systematically discussed. Then from the view of glacial lake inventory and glacial lake hazards study, the glacial lake was defined as natural water supplied mainly by modern glacier melting water or formed in glacier moraine's depression. Furthermore, a complete classification system of glacial lakes was proposed based on its formation mechanism, topographic feature and geographical position. Glacial lakes were classified into 6 classes and 8 subclasses, i.e., glacial erosion lake (including cirque lake, glacial valley lake and other glacial erosion lake), moraine-dammed lake (including end moraine-dammed lake, lateral moraine-dammed lake and moraine thaw lake), ice-blocked lake (including advancing glacier-blocked lake and other glacier-blocked lake), supraglacial lake, subglacial lake and other glacial lakes. Meanwhile, some corresponding features presented by remote sensing images and quantitative indices for identifying different glacial lake types were proposed so as to build a universal and operational classification system of glacial lakes.
The upper Jingjiang reach, which is located at the beginning of sandy channel downstream from the Three Gorges Reservoir (TGR), is undergoing continuous erosion. As a response to riverbed erosion, there has been an obvious water level drop during the dry seasons in the past decades. And this phenomenon has drawn much attention because of its close connections with irrigation, navigation, water environment, dike safety, and so on. In this article, by using the reorganized data of the gauging stations, elaborate efforts were made to examine the characteristics of the low water level in upper Jingjiang reach, including the variations in the same discharge, the same stage and the annual minimum. Besides, the impacts of the TGR operation in dry seasons were also analyzed. This operation mainly refers to the increase of the water release from TGR when its water level almost reached 175 m, which was to ease the drought-prone downstream since 2009. The results show that: (1) the drop of the water level in the discharge of 7000 m3/s were 0.59 m and 1.64 m at Zhicheng and Shashi gauging stations from 2003 to 2015, respectively. On the contrary, the lowest water level has been raised, and the duration of extremely low water level has been reduced since the impoundment of TGR; (2) The drop of low water level was evidently affected by the river bed erosion at Shashi gauging station. The drop of its low water level and the erosion of the nearly river bed were found to be of almost the equal magnitude. However, a smaller drop of low water level at Zhicheng gauging station has arisen, under the comprehensive influences of channel morphology, river bed armoring and channel regulation works; (3) The compensation operation of TGR in dry seasons can raise the monthly-averaged water level from January to April by increasing its water release. In addition, the annual lowest water level was raised, and the extremely low water level duration has been reduced. However, such compensation still cannot eliminate the impact of river bed erosion at Shashi station, even if the compensating discharge reached 2000 m3/s.
Interchannel wetlands as well as multiple channels are crucial geomorphologic units in an anastomosing river system. Planform characteristics and developing level of interchannel wetlands and multiple channels have effect on anastomosing rivers. To understand the role that interchannel wetlands play in the development of the anastomosing river, a study was carried out at the Maqu reach of the Yellow River, a gravel-bed anastomosing river characterized by highly developed interchannel wetlands and anabranches. Geomorphologic units in the study reach were extracted from high resolution satellite imagery in Google Earth, size distribution of interchannel wetlands and interchannel wetland clusters (special combination of interchannel wetlands and anabranches) were investigated, and geomorphologic parameters including ratio of interchannel wetland area to interchannel wetland cluster area (P), shoreline density (Dl) and node density (Dn) were used to examine planform characteristics of interchannel wetland clusters and the development level of multiple channels in the study reach. The results suggest that interchannel wetlands with small or medium size and interchannel wetland clusters with large or mega size are more common in the study reach. The area of interchannel wetland cluster (Su) is highly related to other geomorphologic parameters, P increases with the increase of Su, with 80% of P value being basically the upper limit, indicating that the development of interchannel wetlands and anabranches in an interchannel wetland cluster has entered a equilibrium stage. In contrast, Dl and Dn show a tendency to decrease with the increase of Su due to evolution processes diversity in interchannel wetland clusters with different sizes. There are three main reasons for the formation of interchannel wetland clusters: stream power diversity caused by the meadering principal channel; development of river corridor due to the weakening of geologic structure control; and high stability of interchannel wetlands due to conservation by shoreline vegetation.
Long time-series, spatially-contiguous and accurate precipitation products are one of the most important inputs for various studies, including climate change detection, hydrological modelling, drought monitoring, etc. However, due to its high spatio-temporal variability, precipitation is one of the meteorological elements that are most difficult to estimate. Recently, a new global gridded precipitation dataset that merges gauge measurements, satellite products, and reanalysis data, has been produced. Owing to its high spatial resolution, long time span, and comprehensive combination of different precipitation data sources, MSWEP data have received wide attention since its release. In this study, we first evaluated accuracy of MSWEP monthly precipitation using local gauge measurements in the Three Gorges Dam region, then produced more accurate precipitation data by combining MSWEP and gauge measurements with the GAM (Generalized Additive Model) method, and finally analysed precipitation changes before and after the dam water level rose to 135 m in June 2003. Main conclusions are drawn as follows. (1) No matter what methods are used, estimation accuracy of precipitation shows strong seasonality: more accurate in cold-dry season (spring and winter), while less accurate in hot-wet season (summer and autumn). Gauge measurement and MSWEP are complementary, with the former being more accurate in cold-dry season and the latter being more accurate in hot-wet season. (2) GAM can take advantages of both gauge measurements and MSWEP with flexibility and achieve more accurate precipitation estimation (rmse decreases by 17%-50%, and r increases by 10%-30%). There are still great seasonal variations in accuracy, with rmse being 8-20 mm in spring and winter and 20-50 mm in summer and autumn. (3) Based on the precipitation estimation results obtained in step 2, we found the following phenomena after the water level rose to 135 m in 2003: 1) dam regions south of the Yangtze River show a precipitation reduction over May-October; 2) dam regions in the western part show a precipitation increase over November-April; 3) The northwestern part outside core dam regions shows a precipitation increase over May-October, which is consistent with the results of other studies; 4) precipitation shows an increase in spatial heterogeneity, but a slight decrease in seasonality conveyed by an increase in proportion of precipitation in dry season.
The Tibetan Plateau boasts the greatest lake group in the Asian continent, where the lakes respond sensitively to climate change. For the exorheic lakes, the area changes based on remote sensing data are insufficient to reflect their responses to climatic changes. Water balance analyses of these lakes are needed for understanding the hydrological processes of lake basins and their relationships with climate changes. In this paper, we use the hydrological and meteorological monitoring data in the Ranwu Lake Basin from April to November in 2015 to examine the relationship between water level and runoff and reconstruct flux process line according to continuous water level data. Together with the snowmelt runoff model (SRM) simulation, we analyze the water balance process and its seasonal changes of the Ranwu Lake. The result shows that the total water yield inputted into the lake during the monitoring period is about 18.49×108 m3, and that the glacial melt water is about 10.06 ×108 m3, accounting for more than 54% of the lakes' supplies. Precipitation and evaporation of lake water surface and the lake water storage change have only slight effects on the process of lake water balance. Replenishment of the lake water is clearly seasonal as it depends on rainfall. Under the influence of southern branch of Westerlies, the Ranwu Lake area witnesses high precipitation, which is the main supply source in spring. Due to temperature rise in dummer and early autumn, a large amount of glacial melt water is a dominant factor of the water balance of this lake. With the temperature rise in the future, glacial melt water will occupy higher proportions in the total supplies of the lakes in this area. It will conduce to the speedy rise of the glacial lake level and lead to potential hazard risks.
Based on the global land use / cover data from 1982 to 2011(CG-LTDR), this paper analyzes the characteristics and spatial patterns of cultivated land change since the 1980s. The results are summarized as follows: (1) Since the 1980s, the world's arable land has increased by 528.768×104 km2 with a rate of 7.920×104 km2/a, although the trend is not statistically significant. The world's arable land grew fastest in the 1980s. Areas of cultivated land in North America, South America and Oceania increased by 170. 854×104 km2, 107. 890×104 km2 and 186. 492×104 km2, respectively since the 1980s, showing significant trends with rates of 7.236×104 km2/a, 2.780×104 km2/a and 3.758×104 km2/a, respectively. Areas in Asia, Europe and Africa decreased by 23.769×104, 4.035×104, 86.76×104 km2, with rates of -5.641×104 km2/a, -0.813×104 km2/a and -0. 595×104 km2/a, respectively. Only Asia revealed a significant reduction trend. (2) Since the 1980s, the increased cultivated land in the world has been mainly converted from grasslands and forests, accounting for 53.536% and 26.148%, respectively. Newly cultivated land was mostly distributed in southern and central Africa, eastern and northern Australia, southeastern South America, central US, Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among these regions, Botswana in southern Africa has the highest proportion of increased arable land, an increase of 80%-90%. (3) Since the 1980s, a total of 1071.946×104 km2 of arable land has been converted to other types of land, mostly grasslands and forests that account for 57.482% and 36.000%, respectively. Global reduction of arable land was mainly found in southern and central Africa, central South America, southern Russia and southern Europe (Bulgaria, Romania, Serbia and Hungary). Among these regions, southern Africa experienced the highest reduction of 60%. (4) Cultivated lands in all continents had a trend of expanding to high latitudes, and most countries in the world are characterized by expansion of newly cultivated land and reduction of cultivated land in the earlier period.
Aiming at examining the responses of agro-climate resource to climate change in Northeast China, this study explores the 1960-2099 daily climatic data of regional model simulation in RCP_4.5 and RCP_8.5 scenarios, assimilated with 1961-2010 ground observations from 91 meteorological stations. Agroclimate heat resources and water resources in scenarios are analyzed and the findings are obtained as follows: (1) The annual mean temperature decreases from south to north and is projected to increase across the study region. Obviously, the temperature is higher in the high emission scenario. The annual mean temperature of the baseline, RCP_4.5 and RCP_8.5 is 7.70 ℃, 9.67 ℃ and 10.66 ℃, respectively. The changes of other agro-climate heat resources are similar with those of the temperature. For example, the start date ≥10 ℃ has advanced by 3 d and 4 d; the first frost date has delayed by 2 d and 6 d; the growing season is prolonged by 4 d and 10 d; and the accumulated temperature ≥10 ℃ has increased by 400 ℃·d and 700 ℃·d, respectively. In addition, water resources have a slight increase. (2) The average temperature growth rate of climatic trendency is 0.35 ℃/10 a historically. The highest increasing rate of annual average temperature under the RCP8.5 scenario is 0.48 ℃/10a in the high emission scenario, compared with 0.19 ℃/10a under the RCP4.5 scenario in the low emission scenario. By the end of this century, the warming trend in RCP_8.5 would be faster than that in RCP_4.5 especially in the north of the study region. Other agro-climate heat resources have similar trends with the temperature, but their spatial distribution varies in different parts of the region. Precipitation in growing season is projected to increase although the trend is not statistically significant and has distinct inter-annual variations. Precipitation increases in the east part of the study region, while it decreases in the west. Overall Northeast China is getting warmer and wetter in the future with increased heat resources. However, the imbalance with water resources may have negative impacts on agricultural productivities.
Prone to natural disasters, China badly needs a research into its spatio-temporal distribution of natural disasters and the corresponding grain loss to improve grain security and achieve sustainable development. By means of Python Programming Language and on the basis of grain production loss over Chinese 31 provinces from 1949 to 2015, this paper first constructed disaster intensity index to analyze temporal features of different natural disasters, and with trend analysis as well as ESDA to analyze spatial characteristics in different provinces. Then the paper collected crop planting data to calculate and test the spatio-temporal characteristics in grain loss through estimation model on grain loss, defining grain loss rate and geodetector. The conclusions of paper are: (1) compared with the curve of disaster-affected areas, disaster intensity index constructed in this paper could better present temporal changes of natural disasters; (2) China alternately suffered from flood and drought between 1949 and 2015 and in the coming 5 to 10 years the main suffering would be flood; (3) the ranking of natural disasters is: drought>flood>low temperature >hail> typhoon, among which, the areas affected by drought and flood occupied more than half of the total; (4) natural disasters show clear spatial characteristics and the ranking of regional areas prone to disasters is: eastern region> western region; northern region > southern region. Generally speaking, northern region is prone to only one particular natural disaster while southern region tends to suffer from several natural disasters in the meantime; (5) the sum of natural disasters, drought, hail and low temperature, with their random distribution in space, presented unclear spatial autocorrelation, while flood and typhoon, with their clustering model in space distribution, showed clear spatial autocorrelation; (6) from 1949 to 2015, the general temporal changes of disasters, grain loss amount and loss rate showed a feature that the figures would rise first, and then dropped with the critical point in 2000. Meanwhile, they had significant heterogeneity in spatial distribution, great difference in single-factor explanation power, and multi-factor interaction showed a nonlinear enhancement relation. The distribution of hot and cold spots on both sides of the Hu Line presented a polarization pattern and the gravity center of grain loss gradually moved northward. Accordingly, this paper proposes that our government should adopt different precautionary measures in different regions of China: measures against drought and hail in Northwest China; measures against drought and waterlogging in Northeast China; measures against flood and low temperature in Central China; measures against waterlogging and typhoon in coastal areas of Southeast China. And our government should show more concern to and formulate feasible protection plans for hostile-environment Northwest China and high-grain-production Northeast China so that a good harvest in grains could be guaranteed.
Natural ecosystems supply tangible products and intangible services, which are demanded and consumed by human beings. Therefore, supply and demand make up the dynamic process of ecosystem services flowing from natural ecosystems to human society. The process of identifying, measuring, mapping and conducting an equilibrium analysis of the supply and demand of ecosystem services is beneficial for the effective management of natural ecosystems and optimal allocation of natural resources. Moreover, this can provide theoretical support to payments for environmental services and ecological compensation, thus promoting ecological security and sustainable development. Although the study of ecosystem services supply and demand is important, related studies are limited in China and are mainly focused on Europe and North America. Based on the theory and case studies conducted in China and other countries, this paper first presented the definition of ecosystem services supply and demand, including actual supply, potential supply, satisfied demand, and total demand. Second, the classifications of ecosystem services were compared based on their spatial characteristics. Third, the methods of mapping ecosystem services supply and demand were divided as follows: (1) land use estimation, which needs simple operation and limited data, may cause errors due to the loss of internal heterogeneity and boundary effects; (2) ecological process simulation is mostly applied in water-related ecosystem services, showing detailed and reliable results with multi-calculation; (3) spatial data superposition, which is an ideal method for mapping ecosystem services with complete spatial data sets; (4) expert knowledge, where the mapping of ecosystem services supply and demand is decided by a group of experts or is based on the previous related findings; however, the mapping principle followed in a local study may not be applicable to studies conducted at other places; and (5) the use of integrated models InVEST (Integrated Valuation of Ecosystem Services and Trade-offs), which is suitable for supply analysis, and ARIES (ARtificial Intelligence for Ecosystem Services), maps service flow from natural ecosystems to human beings. Finally, we discussed the equilibrium analysis framework for ecosystem services supply and demand from three angles: actual supply and potential supply, satisfied demand and total demand, and the spatial and quantitative relation between supply and demand.
This paper created a land use classification system of production-living-ecological spaces based on analyzing the theories of production-living-ecological spaces and commanding the dialectical relationships between land use types and land use functions. The classification system perfectly connected to the state standard of land use classification. Based on this system, we examined the spatial and temporal patterns of production-living-ecological spaces in China between 1990 and 2010. The results showed that: (1) The production spatial pattern almost unchanged between 1990 and 2010, and the production spaces were mainly distributed in the southeast of the Hu Huanyong Line, including Northeast China Plain, northwest Xinjiang, Ningxia, Lanzhou-Xining, Sichuan Basin, Bohai Rim, Yangtze River Delta, Xiamen-Quanzhou-Zhangzhou, and Pearl River Delta, where China's urban agglomerations and main grain production areas were located in. (2) Living spaces were mainly distributed in China's urban agglomerations and cities, showing a spatial pattern of "high in the east and north regions, while low in the west and south regions". Its spatial expansion varied in different areas. Large-scale expansion of living spaces appeared in the Bohai Rim, Yangtze River Delta and Pearl River Delta, while small-scale and point-type expansion in the major provincial capitals. (3) Ecological spaces were mainly distributed in the northwest of the Hu Huanyong Line, showing a spatial pattern of "high in the west and south regions, while low in the east and north regions". The expansion of ecological spaces were mainly in the Loess Plateau, Hulun Buir Glassland and Tianshan Mountains, while the reduction of ecological spaces were mainly in the Northeast China Plain, North China Plain, Yangtze River Delta, Pearl River Delta, Ningxia and Xinjiang. (4) Industrialization and urbanization were the basic driving powers of changes of China's production-living-ecological spaces. The main reasons for regional spatial differences across China included farmland cultivation in Northwest and Northeast China, rapid urbanization in North China, Bohai Rim, Yangtze River Delta and Pearl River Delta, and reversion of farmland to forestland in the Loess Plateau. This research was valuable for the studies on classification and evaluation of production-living-ecological spaces.
China's investments, financial incentives and deductions on ecological conservation are based on the county level. Therefore, the monitoring and assessment on the effects of ecological conservation at the county level is significant to provide a scientific basis to the ecological and environmental quality assessment of counties. This paper quantitatively estimated the dynamics of high-quality ecosystems and the vegetation coverage in the past 15 years, and examined its relationships with the number of ecological conservation programs at the county level. Then it assessed and discussed the effects of ecological conservation measures in county's ecological changes and its regional suitability. The results showed that the proportion of high quality ecosystems higher than 50% was primarily observed in counties of Northeast China, subtropical southern China and southeastern Qinghai-Tibet Plateau, and the proportion lower than 20% was mostly found in counties of Northwest China, karst region of Southwest China and the North China Plain. In recent decades, ecological conservation focused on ecological fragile regions, so there are more than five ecological conservation programs in most counties of the Three Rivers Source Region in Qinghai Province, southeastern Tibet, western Sichuan, Qilian Mountains, southern Xinjiang and other parts of Western China, while there is one or no one found in coastal eastern China. In the past 15 years, the area proportion of high-quality ecosystems in 53% of the counties has increased. The vegetation coverage of counties in the Loess Plateau, Huang-Huai-Hai Plain, Beijing-Tianjin-Hebei region, Sichuan-Guizhou-Chongqing, and Guangdong and Guangxi provincial units has increased significantly. However, it has decreased in northern Xinjiang, central Tibet, central and eastern Inner Mongolia, Yangtze River Delta and other parts of China. The relationships between the numbers of ecological conservation programs and the indicators responding ecosystem restoration such as high-quality ecosystem and vegetation coverage do not show positive correlations. It is recommended that ecological conservation projects should be planned and implemented according to the distribution of high-quality ecosystems, and the restoration measures such as afforestation should follow natural principles and regional variations under the background of climate change.
Wu Shangshi (1904-1947) is considered one of the outstanding modern geographers emerging in the early 20th century in China. It is partly a result of the introduction of modern sciences from the West. Wu graduated as a gold medalist in Sun Yat-sen University （SYU) in 1928. He was then granted scholarship to study geography in France. He studied at the University of Lyon and the University of Grenoble under the supervision of A. Allix, M. Pardé and R. Blanchard,who was one of the best known students of V. de la Blanche. In 1934, Wu finished his study in France and returned to SYU to serve as a professor of geography. He was head of the department in 1939-1945, the most difficult and perilous period during the Japanese invasion. The university moved constantly to flee the flames of war. The thousands of miles across south and south-west China became Wu's research field. To continue one's work under such circumstances required an extraordinary determination and dedication to science. Excessive hard work in tough environments ruined his health. Wu died in 1947 at the age of 43.
Among the second generation of Chinese modern geographers, Wu was a rare example of an integrated geographer. He combined comprehensive and complex geographic thought with a balanced approach between holistic perspective and detailed research. In addition, he possessed an outstanding ability to conduct field work. As such, many of his research findings have withstood the test of time and remain relevant to this day. For instance, Wu proposed "one belt and three arcs" to summarize the distribution of the mountain ranges in China. On the long debates of the stratigraphic sequence of the red bed formations "Danxia" and "Nanxiong", Wu suggested an alternative viewpoint that the two formations could be deposited at approximately the same time but in different faces and it has been confirmed by modern geologic investigation some 50 years later. Both contributions were listed on the "Great Geographical Discoveries of China in 100 Years". Wu's pioneering work covered a wide range of disciplines of geography: geomorphology, hydrography, climatology, cartography,regional geography, etc. Most of his research involved a combination of keen observation, incisive logical deduction, broad knowledge and professional instinct. The present paper summarizes Wu's major accomplishments which are scientifically significant to the establishment of modern and contemporary geography in China. It also reveals that Wu's scientific thought and practice can be traced to the French schools of geography and other Western countries.
However, his accomplishments cannot be fully appreciated without understanding of the significant role that traditional Chinese culture played in his consciousness. Wu's social connections and educational background could have easily allowed him to move within the power circles and become part of it. Yet he remained upright and forwent opportunities for fame and fortune, choosing Geography as his life's work. Wu was also a renowned educator whose list of students features names such as Luo Kaifu, Zeng Zhaoxuan, Xu Junming etc. The Geography Department in SYU has been being one of the important bases of China's modern geography science, to which Wu's crucial contributions cannot be left unrecognized.
A scientific park is under construction by the City Hall of Guangzhou at the site where Wu identified an ancient wave-cut cliff in 1937. Wu' statue placed in the park was designed by the well-known sculptors
