Aerial Remote Sensing in Shanghai Municipality

Aerial Remote Sensing in Shanghai Municipality

Cheng Zhimu jiang Zhixiang
Shanghai Office of Remote sensing Comprehensive research Shanghai, China

Introduction
Shanghai used to be an balanced developed large city. It left series of problems for us to solve. With the development of urban construction at top speed in Shanghai around ten years, it makes the “city Syndrome” arise quickly, such as decrees of land resource, traffic jam, deterioration of ecologic environment. Aerial remote sensing comprehensive research has been taken since 1988 in Shanghai for grasping the present situation of Shanghai municipality, finding the crux of problems, surveying for developing pudong area and reconstructing the old urban area. This research will be finished in three years.

There are seven projects including twenty-four specific items, such as urban construction and traffic , gardens afforestation , harbour, the evaluation of surface water resource, the present situation of land use in town and city, beach resource, farmland, fruit trees, geology, geomorphology, etc.

Contents of Aerial Remote Sensing
According to the different purpose of research, visible spectral aeorphotograph and thermal infrared scanning have been taken.

1. 1:10,000 Color Infrared Photograph in Urban Area and Adijonting Area of Town and city in Shanghai municipality.

The area covered by color infrared photograph is 1350 km2. It provided abundant information for investigation the present situation of afforestation and environment, the present situation of land use etc.,

2.Remote sensing research for the Present Situation in the Central Part of Shanghai City.

Investigation was taken in four rush periods of passenger and cargo transportation from 7:30 to 9:00, 9:00 to 11:30 , 14:30 to 16:00, 16;30 to 19:00 . At this four periods, remote sensing aero plane flew over the eight EW main traffic lines and five SN main traffic lines, and also over Zhongshan Huan Road. With the flying, 1:10,000 visible spectral aero photograph has been taken. In the evening, thermal infrared scanning was taken, and the track motor of vehicle can be recognized according to the difference between motor and ground.

Accumulated total length of Photography and scanning is about 500km.

3. 1:40,000 thermal Infrared scan for the Central City

Thermal infrared scan was taken in noonlate and noontide. Each time it covered 350 km2 . At the same time, the temperature of different kind of surface features was measured with the portable infrared radiometer

4. 1:35,000 color infrared Photograph of Seashore

The range of the investigation is form Shape town near the north of Huangzhou gulf along the coastline to Xu liujing near the south Changing River, and its total measured length is about 700km.

5. remote sensing research for the water Pollution in the Area of Changjiang River Mouth.

In order to grasp the present situation of water pollution and the dynamic spared pattern of polluted water which flows into Changjiang River from Liuhe and Huanpu River, we organized mutitime aerial remote sensing flying. We flied back and forward 7 times over the river as long as 100km from rising tide to ebb tide, and we obtained a full tide comprehensive remote sensing information. During the flying, 8 vessels including ships and boats were arranged over the river We investigated at in 13 sites to get water sample, measure water temperature and current velocity.

6. 1:60,000 Color Infrared Photograph in Shanghai Municipality

Including water area the areas near other provinces, the covered are reached 13900 km2 . It is used for construction of towns , farm land conservancy and investigation of the present land use.

Present Achievements
1. Remote Sensing Comprehensive Research for afforestation in Shanghai Municipality

The research includes the investigation of the present situation of afforestation, the analysis of afforestation changes, afforestation and environment, and planning of afforestation. We set up the data bank of city afforestation. The researches are on the basis of the afforestation information appeared on the color infrared aerophotograph. They measured the whole city’s public greed area, special green area, nursery of young plants and the covering area of shade trees. The results of research show that:

[1] The present situation of afforestation of Changjiang region is better with covering rate of 22% . The rate nashi region in the center of the city is only 5.1%

[2] The average afforestation covering rate is only11.7% in the city at present (Fig. 1)

Figure 1 The present afforestation sitution in Shanghai municipality (covering rate of afforestation)
The average green area is 4.63m² for each person.

[3] According to the comparison of two periods data of the aerophotograph between 1964 and 1988, we found that in range of 154 km2 in the central city, the total reduced green land is 2.6km2 in 26 years.

The above research achievement provides the reliable evidences for the administration of afforestation, planning of Shanghai municipality.

2. Evalution of surface water resources
in order to find a new drinking water source for Shanghai municipality at Yangtse River mouth, we made a regression analysis on the basis of the density of colors information appeared in the color infrared photograph and the water information got by synchronous field investigation . it shows that there is a close relatively among the ratio of density between red and green (M) , Chemistry Oxygen demanded (COD), Biology Oxygen demanded (BOD) and Oxygen Dissolved (DO) . The regressive equation between M and K [Composite pollution index) has been set up. (Fig.2)

Figure 2 Relatives of color density ratio and pollution index
The research Shows : (1) There are 30 main pollution sources along the 70KM river from Xu Liujing to wasong Kou (2) There is no serious pollution area in the upper reaches of Liuhe River within Jiangsu province. There are some pollution sources in the low reaches of Liuhe River,including the west drainage polluted water area, Baoshan steel factory, Shidong Kou electric power plat and Huangpu River. The pollution in those areas is in high density, and the pollution is spreaded in large area. While at ebbing tide, the longitudinal spread distance can reach to 10KM , and with 2 KM pollution of high density (Fig.3)

Figure 3 High density polluted water drainage from the west drainages mouth
The crosswise spread can reach the range of 1.8 KM (about- 10M in depth in water area).

The longest distance which polluted water flows against current is 6.5 KM when it’s at rising tide, but the high density polluted water area is within the range of 1.5 KM (3) After a composite analysis, we found that the water quality is better from Beimao Kou to Tanghuang Kou, Liuhe Kou to Luojing , and it is similar to the background of Changjiang River (II level) , where the coastline is steady. It’s a ideal resource area of drinking water.

3. The Proofs of the Benefit of Polluted water Drainage in Zhuyuan
The polluted water drainage in Zhuyuan is an important project of confluent polluted water’s harness in Shanghai municipality. The aim is to use tubers for gethering industry polluted water and domestic sewage in urban area to the nearby regions of Zhuyuan Kou, and then drain them away, so as to be purified and diluted with Changjiang River water.

In order to get all kinds of parameters of nearby drainage of Chanjiang River running water, on basis of te seven periods remote sensing information and synchromes inspective data, we have studied the polluted water which comes from Huangpu River, west area drainage and south area drainage systematically, and its longitudinal and crosswise spread dynamic pattern in different tide, when it entered Changjiang River. We also made a systematic study about the nature. diluting ability of Changjioang River running water near Zhuyuan Kou area. It shows that there is an obvious interface in the area which is 1200-1300 M away from bank. The nature diluting ability outside of the interface is 3-4 times greater than the the inside (Fig.2.)

So we suggest that the pipe of drainage polluted water must be arranged outside 1200-1300m away from the bank, so that the polluted water from urban area can be drained into east sea through Changjiang River. Otherwise, some parts of polluted water will stay in Changjiang river, and Changjiang River will be serious polluted.

Figure 4 Curves of crosswise spread coefficient by calculated according to the scan image
4. remote Sensing research for Beach Resource
According to the remote sensing information comparison in Dec.1982 and Nov. 198, we found that the beach of Congming islandis moving towards East Sea at the average speed of 160M per year (The highest spread is 420M per year). Within 7 years, the land increased by 4.4*104 acre. At the same time, the beach in Nanhui county increased by 2.48*104 acre. Some sections of the north beach of Hangzhou gulf has been washed away and some of them become silted up. But the total area is less changed.

5. Remote Sensing Research for the Thermal Field and the Conditions of the Pollution spread of the Cushion Coat below Atmosphere
We make a systematic comparison and analysis according to the category of surface features interpretated on 1:50,000 color infrared aero photograph and the meteorological satellite images. it shows that: (1) The thermal field is distributed along Huangpu River at NE—SW , and its shape is accordant with the buildings outline in urban area. (2) There are three higher temperature areas and a lower temperature area in the urban area. The formal area is accordant with three industry areas in the east, west and south of Shanghai, especially those industry that has something to do with the steel factory , textile mill and printing and dyeing mill which are in higher coal consumption. It shows that there is a serious thermal leak in those district. The lower temperature area is accordant with the district of the building with gardens. That is to say afforestation produces good results to the city climate. The average daily temperature in the abnormal thermal area is 1 degree higher than that in the around area ( The ground temperature can be 5—10 degree higher than that in the around area (The ground temperature can be 5—10 degree higher than the surrounding area).

6. Remote Sensing research for the present situation of Land Use in the Adjoining Area between Urban and Rural Area.
According to the 1:10000 color infrared aerophotograph, we compiled land use maps and land use change maps from 1981 to 1988.

It shows that the adjoining area of town and city has become the uneven region which is composed of factory, farm houses and residential areas, because of the acceleration of urbanization in recent years. The plan of afforestation area set in The overall planning of Shanghai municipality” is difficult to carry out. Recently, the land of the adjoining area of town and city is highly reduced, and its distribution is in disorder, environment becomes worse. So it seems urgent to establish a planning program.

Moreover, We also make use of the remote sensing technology to investigate the open sports installations , the present situation of solid wasted material stack and the land use in pudong developing area. At the same time, we provided the latest image information for choosing the place of subway engineering, the flyover of Zhongshan Bei Road, Baoshan steel factory and the Jingshan petrochemical factory. Based on the two years’ practice, it fully proves that it has obvious social and economic benefits to useaerial remote sensing technology in urban development and planning.