The impact of land cover changes on land surface temperature in ho chi minh city based on landsat imagery

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURAL AND FORESTRY NGUYEN CAM TU THE IMPACT OF LAND COVER CHANGES ON LAND SURFACE TEMPERATURE IN HO CHI MINH CITY BASED ON LANDSAT IMAGE

THAI NGUYEN UNIVERSITY

UNIVERSITY OF AGRICULTURAL AND FORESTRY

NGUYEN CAM TU

THE IMPACT OF LAND COVER CHANGES ON LAND

SURFACE TEMPERATURE IN HO CHI MINH CITY BASED

ON LANDSAT IMAGERY

BACHELOR THESIS

Study Mode :Full-time

Major :Environmental Science and Management

Faculty :Advanced Education Program Office

Batch :2014 - 2018

Thai Nguyen, 25/09/2018

Thai Nguyen University of Agricultural and Forestry

Degree Program Bachelor of Environmental Science and Management

Thesis Title The impact of Land Cover Changes on Land Surface

Temperature in Ho Chi Minh City based on Landsat Imagery

Supervisor (s) Assoc Prof Tang-Huang Lin

MSc Nguyen Van Hieu Supervisor’s signature

Abstract:

Along with the growth of national and social economics ,the urban development is taking place strongly in Viet Nam during the past decades, especially in megacities The assessment of land use changes is a very important issue among the impacts of urbanization ,serving as a foundation for land use planning.In this study , the multi-spectral and multi-temporal satellite imagery were used to investigate the impact of Land Cover Changes (LCCs) on Land Surface Temperature (LST) in Ho Chi Minh City(HCMC), Vietnam Three sets of Landsat imageries covered a period of 20 years

in HCMC from 1998 to 2017 are acquired for examining the impact of LCC , including Landsat 5 Thematic (TM) in 1998 and 2008 and Landsat 8 Operational Land Imager (OLI) in 2017 Supervised methodology is employed with maximum likelihood technique land cover classification The land covers of the study area are categorized into four different classes namely vegetation, urban, bare soil and water

The results show that during the last two decades the area changing vegetation ,urban , bare soil have been decreased by 16.24% and 12.4% , while urban and water have been increased by 27.19% and 1.44% respectively The most significant changes is the bare soil transited to urban type (20% in area) As a consequence of the land cover changes , the LST was boosted up to 0.42 degree Celsius after 20 years This study also indicates that the impacts of LCCs on LST was affected by the development of new urban city and the population growth which play an important role in the Land Cover Changes as well as Land Surface Temperature

Keywords: Ho Chi Minh City, Land Surface Temperature, Land Cover

Changes Number of pages: 57

Date of Submission:

25/09/2018

ACKNOWLEDGEMENT

From bottom of my heart , I would like to express my deepest appreciation to Associate Professor Tang-Huang Lin who in spite of being extraordinary busy with his duties , took time out to hear , guide, keep me on the correct path and complete report during the time of conducting the research at Center for Space and Remote Sensing Research (CSRSR) of National Central University (NCU)

I also wish to express my deep gratitude to MSc Nguyen Van Hieu who gives

me an opportunity , guidance and support me to complete thesis

For my friends in Taiwan, I would like to send my best wishes to all of you : Minh Nguyen, Chang Jui-Chung, Tzu-Ying Chen Thank you for always listening to

me and helping me to overcome the weakness and hardships during the time I conducted my internship in NCU You are all made up my life in Taiwan more meaningful and those unforgettable moments will go along with me forever I sincerely thank the additional members of CSRSR who have contributed to my work Last but not least, I take this opportunity to record my sense of gratitude to my families and friends who encourage and backing me unceasingly

Thai Nguyen, 20/09/2018

Student

Nguyen Cam Tu

TABLE OF CONTENT

List of Figures vi

List of Tables vii

List of Abbreviation vii

PART I INTRODUCTION 1

1.1.Research rationale 1

1.2.Investigate the study area 3

1.3 Statement of Problem 4

1.4.Objectives of study 5

1.5 Significance of study 6

1.6 Limitation of Study .6

PART II LITERATURE REVIEW .7

2.1.Land Use/Cover Change 7

2.2.Land Surface Temperature 10

2.4 Land Cover Change and Land Surface Temperature in Vietnam3.Impact of Land Cover Change on Land Surface Temperature 11

2.5 Related study on Land Cover Change and Land Surface Temperature over the world 13

PART III.METHODS 16

3.1 Material and Data 16

3.2 The objectives and the scope 17

3.3 Methodology 18

PART IV RESULTS AND DISCUSSION 31

4.1 Results of Land Cover Changes 31

4.2 Change Detection 34

4.3 Results of Land Surface Temperature 44

PART V.CONCLUSION 49 REFERENCES 51 APPENDICES5 55

LIST OF FIGURES

Figure 1 The map of Study Area 4

Figure 2 Methodology of the impact of LCC on LST 18

Figure 3 Method for Pre-Processing of remote sensing data 19

Figure 4 Layer Stacked images of 1998(a), 2008(b) and 2017 (c) 22

Figure 5.Clip Area of Ho Chi Minh City for 1998,2008 and 2017 23

Figure 6 Flow chart of Land Surface Temperature computation 26

Figure 7 Land Cover Change map of 1998,2008 and 2017 30

Figure 8 The percentage of area of each land cover changed in 1998-2017 31

Figure 9 Change Detection of HCMC from 1998-2017 33

Figure 10 The percentage of Land Cover Change from 1998-2017 35

Figure 11 Brightness Temperature of 1998,2008 ,2017 band 10 and band 11 36

Figure 12 Normalized Difference Vegetation Index map for three diferrent year 1998,2008 and 2017 38

Figure 13 Green Vegetation Fraction of 1998,2008 and 2017 40

Figure 14 The Emissivity map for (a)1998, (b) 2008 and (c)2017 41

Figure 15 Land Surface Temperature map of 1998,2008 and 2017 43

Figure 16 The relationship between Land Cover Changes and the Mean of Land Surface Temperature in degree Celsius over two decades ( 1998-2017) 46

LIST OF TABLE

Table 1 Description of the satellite images used in study 16

Table 2 Details of Landsat 5 TM Satellite Images 20

Table 3 Details of Landsat 8 OLI/TIRS Satellite Images 21

Table 4 Land Cover Classification scheme 24

Table 5 Thermal Constants of Landsat 5 TM and Landsat 8 OLI/TIRS 27

Table 6 Accuracy Assessment of Land Cover between 1998,2008 and 2017 32

Table 7 Percent and Area of Land Cover Change Detection during the period from 1998-2017 34

Table 8 The absorb temperature of HCMC from 1998-2017 44

Table 9 The land cover changes on land surface temperature from 1998-2017 46

Table 10 LST validation by the meteorological temperature data 48

ABBREVIATION

ERDAS Earth Resources Data Analysis System

GIS Geographic Information System

HCMC Ho Chi Minh City

LCC Land Cover Change

LST Land Surface Temperature

LULC Land Cover Land Use

NDVI Normalized Difference Vegetation Index

NDBI Normalized Difference Built Index

OLI Operational Land Imager

TM Thematic Mapper

USGS United State Geological Survey

PART I INTRODUCTION 1.1 Research rationale

Urbanization is the physical growth of rural or natural land into urban areas as a results of population immigration to an existing urban area (Jahan,2012).Urbanization

is also defined by the United Nations as movement of people from rural to urban areas

with population growth equating to urban migration According to Tran Thi Van el

al.,2010 stated that urbanization is a main type of land use and land cover change in

human history Rapid urbanization and industrialization have resulted in sharp land cover change Urban change not only impacts on land cover but also on urban climate (Tran T.Van, 2010) The growing density of population and changing economic activities are determining factors of urban land use change (P.Prabu, Mithas Ahmad Dar, 2018) The population growth and socio-economic development result rapid transportation increasing, urban expansion reached to suburban areas The increase in the world’s population recently has maximized the effects of the economic and agricultural activities The United Nations projected that half of the world's population would live in urban areas at the end of 2008 (UN,2008) It is predicted that by 2050 about 64% of the developing world and 86% of the developed world will be urbanized (https://www.unfpa.org/urbanization) That is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and Asia Notably, the United Nations has also recently projected that nearly all global population growth from 2017

to 2030 will be absorbed by cities, about 1.1 billion new urbanites over the next 13

years (Barney Cohen et al.,2015) Urban areas are known to be the unhealthy areas or

places for people to live

A large amount of forest and agricultural land has been converted into housing, infrastructure and industrial estates Thus, it has a great impact on environment and climate Urban areas tend to experience a relatively higher temperature compared with the surrounding rural areas (S.Rajendran, 2009) There are two main causes engaging

in urbanization : forcing people from rural areas to urban areas and drawing people into city

Meanwhile, in Vietnam , people are experiencing an unusual warm weather which

is getting worse especially in urban areas like Ha Noi and Ho Chi Minh City is one of the most urbanized areas in Vietnam In addition, Ho Chi Minh City (HCMC) is placed in the crossroad of several regions; the South-East, the South of Central Highland , the South of central coasts and the Mekong delta These regions possess a great variety of resources , agricultural , aquatic and oil resources of which they are dominant (V.Thanh, 2005) HCMC situation is advantageous, in the middle of a vast rural zone constituted of a rice storage and a vast industrial plantation With an important harbor system, HCM became the most important economical pole of the country HCMC is also considered as the Central Business District of the country for its commercial areas are known in its role as the financial and business center of Vietnam.The continuous population growth economic development,with an increase in vehicular trips, cause a big problem in the city making it inconvenient for the people as the temperature in urban areas gets warmer from environmental changes

Therefore, HCMC is selected as the study area for it is one of the biggest and busiest cities in Vietnam The continuous development of the city can highly affect the temperature particularly in summer time In order to evaluate and monitor the temperature as well as the impact of urbanization according to the land cover changes

detection results on land surface temperature of HCMC during a 20-year period from

1998 to 2017 Landsat imageries will be used by the help of remote sensing and GIS technology , which were well-developed and highly applied to different fields such as atmosphere, geology, hydrology etc can be an effective way in knowing the relationship between Land Cover Change and Land Surface Temperature of HCMC

1.2.Investigate the study area

Ho Chi Minh City, also known as Saigon, is one of the urbaniest and most

prosperous cities in Vietnam which is located in the South with the geography between 10º 46'10" N longitude and 106º 40'55" E latitudes (HCM statistical source)

It is enclosed by Tay Ninh and Binh Duong provinces in the north, Dong Nai and Ba Ria - Vung Tau provinces in the east and Long An Province in the west(Figure 1) The total land area is 2095.01 km² and the city has 19 urban districts which

aredesignated urban or suburban and 5 rural districts The city has a tropical climate, specifically a tropical wet and dry climate, with an average humidity of 78–82% The weather is divided into two distinctive seasons The rainy season, with an average rainfall of about 1,979 millimeters annually (about 159 rainy days per year), usually begins in May and ends in late October The dry season starts from December to April.The mean temperature is 28°C(82°F), with little variation throughout the year.The highest temperature recorded was 40.0 °C (104°F) in April while the lowest temperature recorded was 13.8°C (57°F) in January On average, the city experiences

between 2,400 to 2,700 hours of sunshine per year (H.Storch et al.,2011)

According to statistical data the population density has increased from 552 pers/km² in 1985 to 3,067 pers/km² in 2006 in urban areas about 10,905 pers/km and rural areas about 648 pers/km² (N.D.Hoa, 2014)

The population growth causes the spatial expansion being through encroachment into adjacent agricultural and rural regions, especially in the northern part of the city due to the advantages of landscape and relative high topography Hence, the study area

is limited to this part

In this study, the central business district is investigated to become the main study area which is the place where the urbanization process is happening strongly in

recent years

Figure 1 The Map of Study area

Source: Google Earth Pro

1.3 Statement of Problem

Before 1990, the line of immigrants flocking to Ho Chi Minh City to earn a job and earn a better living in Ho Chi Minh City was increasingly year by year HCMC

is considered as the country’s central business district The development of urban economy ,particularly , the private sector and foreign investments provoked a demand for the environment protection in the city which is in a process of fast urbanization Hence, HCMC is home for the most important business centers and the main destination for people seeking job opportunities That is an evident for increasing in population leading to establishments of more buildings, skyscrapers and houses which eventually deteriorates the urban environment such as air pollution It can affect the people dwelling on or near the area and the natural environment as well

With this , the study will be conducted to answer these question:

1 How obvious is the urbanization of HCMC affecting to the Land Cover Change

detection results from 1998 to 2017?

2 What is the impact of Land Cover Change on Land Surface Temperature in

The general aim of this study is to evaluate the impact of Land Cover Change

on Land Surface Temperature in HCMC based on Landsat Imageries during a 20-year period from 1998 to 2017 The specific objectives are:

- To evaluate the land cover change of Ho Chi Minh City during 1998-2017

- To estimate the impact of Land Cover Changes on Land Surface Temperature between 1998 and 2017

- To identify the real situation of Land Cover Change in HCMC from 1998 to 2017

1.5 Significance of Study

This study could provide additional information on the impact of Land Cover Change on Land Surface Temperature in HCMC Specially, 1) how the land cover change detection affected to land use in HCMC; 2) the rate of change in each category based on Landsat imageries; 3) how the temperature varied in different type

of land cover The findings of this research may contribute to the future planning and referencing of HCMC which can also help the authorities , residents and urban planner

1.6 Limitation of the Study

Although the study has reached its aim, there are still some limitations for this future investigation: (1) this study only focused on the land cover types but not on the building types (composition, construction, height etc of the building); (2) the study did not able to get Landsat imageries with the same months owing to the limitation in the available data of the study area (HCMC), the new generation of open data satellite imagery may address this issue

PART II LITERATURE REVIEW 2.1 Land use/cover change

Land cover change is defined as the change in physical characteristics of land surfaces such as forests, concrete , and water areas Land cover refers to the physical characteristics of earth’s surface ,captured in the distribution of vegetation ,water,soil and other physical features of the land , including those created solely by human activities while land use refers to the way in which land has been used by humans and their habitat, usually with accent on the functional role of land for economic activities (Bujang et al.,2012) Land use affects land cover and changes in land cover affect land use (J.S Rawat,Manish Kumar, 2015) This land cover change can be determined by aerial and satellite imagery in seeing the changes over time by using remote sensing and GIS technology With the information acquired from land cover maps for several different years , researchers can evaluate and detect the causes and effects of the development of an area These maps can assess several environmental concerns Moreover, theses land cover changes connect the socio-economic changes such as the population increase( National Ocean Service NOAA website) With this, many study use Land Cover Change detection in monitoring and evaluating the urbanization of an area on how the area changes from the past to the previous years

On the other hand, the effect of urbanization on land cover change in an area is also conducted by many researchers.Naturally the Earth surface is covered by different land cover types which are mainly distributed based on the environmental and climatical patterns (S.Youneszadeh,N.Amiri, P.Pilesjo, 2015) Urbanization leads to urban spatial expansion due to the demand for development and housing growth, as well as facilities areas to serve human life (Van, 2008) The growth of urban areas has

a significant impact on land cover by replacing areas of vegetation with residential and commercial areas and their related infrastructure, this escalates the land surface temperature (Ibrahim, 2017) Land use/cover change is a dynamic process taking place

on the bio-physical surfaces that have take place over a period of time and space is of enormous importance in natural resource studies Land use/cover change dynamics are important elements for earth resources Land use/cover changes ares the major issues and challenges for the eco-friendly and sustainable development for the economic growth of any area With the population explosion,human activities such as deforestation,soil erosion, global warming and pollution are very harmful for the environment (J.S Rawat, Vivekanand Biswas, Manish Kumar, 2013) There are several more studies related to urbanization and land cover changes which were conducted and most of them aimed to know the influence of urbanization on the alternation of land cover type

2.2 Land Surface Temperature (LST)

Land surface temperature is how hot the “surface” of the Earth would feel to the touch in a particular location From a satellite’s point of view , the “surface” is whatever it sees when it looks through the atmosphere to the ground It could be snow and ice, the grass on a lawn , the roof of a building or the leaves in the canopy of a forest (NASA Earth Observatory website).LST is one of the key parameters for estimating surface energy budget assessing land cover changes and other

characteristics of the Earth’s surface (Ssrivastava et al,.2010).Measuring and analyzing

of surface temperature and surface emissivity by using remote sensing data and GIS analysis is virtually used by various scholars over the world (Mehebub Sahana, Raihan Ahmed, Haroon Sajjad, 2016)

Environmental and urban climate studies use land surface temperature and emissivity data for numerous purposes but mainly to analyze LST patterns and how they are connected to surface characteristics,urban heat island forecasts (Ibrahim, 2017).Urban temperature rise and formation of urban heat island (UHI) has been a concern for more than 60 years (Swades Pal, Sk.Ziaul, 2017).Land surface processes such as changes in the green vegetation fraction are keys for the distribution of UHI and are detectable from satellites (Yonghong Hu and Gensuo Jia, 2009) Besides, Land Surface Temperature derived from remote sensing data is unique source of information

in oder to define surface urban heat islands and it has been widely used as indicator for UHI research.With the introduction of thermal remote sensing ,LST information is available from a series of satellite sensors such as Landsat, MODIS, and ASTER that cover a wide range of the earth surface (Duy X.Tran et al., 2016) In addition ,LST derived from remote sensing imageries might be better to show the hottest and coolest areas as compared to temperature collected from urban weather station(Nichol To,2012) The combination of the land use analysis result with the mean land surface temperature can offer useful information to study the land cover change effects in Ho Chi Minh City

2.3 Impact of Land Cover Change on Land Surface Temperature

Xiaolu Shou and Yi-Chen Wang (2010) have studied about Dynamics of Land Surface Temperature in response to Land use/cover change stated that rapid population growth and continuous exploitation of natural resources during the past century have caused land use/cover change worldwide This study aimed to investigate the impact

of land cover/use change on Land Surface Temperature in a rapidly urbanisation city, Kunming in south-west China Using Thermatic Mapper (TM) imageries of 1992 and

2006 were derived from USGS website to examine how LST responded to urban growth The results showed that rapid urbanization in Kunming altered the local thermal environment,particularly in increseing the LST in the zone surrounding urban core.On the other hand, a group of scholars including S.Youneszadeh,

N.Amiri,P.Pilesjo (2015) conducted a research called “ The effect of Land use change

on Land Surface Temperature in Netherlands” indicated that the inland water and

offshore areas has the highest night land surface temperature in the years of 2003,2006 and 2008 surveyed Addition to that, in the study of Ashraf M.Dewan, Rober J.Corner in Curtin University, Western Australia concluded that the differences between the mean surface temperature and land cover type in the capital of Bangladesh,Dhaka are highly significant The urban built up area has increased by 67% since 1990 Moreover, Clause Rinner and Mushtag Hussain (2011) from Department of Geography , Ryerson Univerisity, Toronto,Canada found out that the average temperatures are substantially higher for commercial resources and industrial land uses while lower temperature for park and recreational land uses as well as water These findings explained how the urban expansion and change in land use/cover can affect the temperature in the urban areas With this outcomes, urban planners and other environmental concerning citizens could make numerous decisions on urban planning and how to lessen the continuous increase in temperature

However, studies noticed an increase in urban growth wih a related decrease in vegetation , which resulted in an alteration of urban microclimate Another study determined the land surface temperature and vegetation abundance relationship Different indices of vegetation indicate an abundance of vegetation ,such as Green Fractional Vegetation(GVF) and Normalized Difference Vegetation Index (NDVI)

A negetaive connection between the NDVI and Land Surface Temperature was revealed ,as well as the green area’s cooling effect due to soil moisture variations, land surface emissivity, albedo and profusion of vegetation resulting in the fall of variable

temperatures of dense vegetation (Ibrahim, 2017)

2.4 Land Cover Change and Land Surface Temperature in Vietnam

Research have done in Hanoi – Capital of Vietnam (Duy X.Tran et al.,,2016) that urbanization was faster in and around Hanoi inner city than in other surrounding areas

by examining the relationship between LST and NDVI, NDBI within each LULC type They discovered that the correlation is not always linear since it may vary between each LULC type as well as being subject to the geographic location and season

This study based on Getis Ord Gi* statistics method (Duy X.Tran et al.,2016) to analyze changes in LST patterns through time The identification of hot spot or cold spot areas by such method does not depend on whether the mean temperature is high

or low so the effect of different LST values throughout time is reduced In general, more than 20% of the city area is always warmer whereas less than 10% of the city area is always colder than the mean zonal LST Hot spots tend to increase through time (from 27.95% in 2003 to 34.61% in 2015) anstrongly correlate with urban expansion

In Vietnam, land use and land cover patterns have undergone a fundamental change due to rapid economic development under its reformative economic policies Urban growth has been speeding up, as a result, an extreme stress to the environment has occured This is particularly true in Ho Chi Minh City where agricultural land has been gradually disappearing each year, converted into urban or related uses Furthermore, because of the lack of appropriate land use planning and the measures for sustainable

development, rampant urban growth is creating severe environmental consequences (Van, 2008)

On the other hand, in the study of Ran Goldblatt, Klaus Deininger, Gordon Hanson

(2018) entitled “Utilizing publicly available satellite data for urban research: mapping

built-up land cover and land use in Ho Chi Minh City, Vietnam”.This research has an

easy method for accurate classification of built-up land cover/use which is performed

by a pixel-based supervised image classification procedure in Google Earth Engine (GEE),using two sources of reference data (adminitrative data and hand-labeled exampled) While many existing classification products characterize urbanization, they are typically limited in their spatial and temporal resolution and characterize urbanization according to definitions that may have limited application in other contexts

Another study have shown that remote sensing provided a straightforward and consistent way to determine LST pattern in a wide region, as well as the thermal differences between urban and rural areas The landsat data is one of the most widely used satellite images for LST retrieving because of its high resolution (120m of TM, 60m of ETM+ and 100m of TIRS) and free download availability from the website of USGS (Dang, 2015) The results obtained in this work show that Da Nang city’s urban area expaned twice from 1990 to 2014, leading the expansion of highest LST from centers of Hai Chau and Thanh khe districts The impact of urbanization on the LST

in Da Nang City additionally confirmed by the increase of differential temperature between downtown and suburban areas, from 7.3ºC in 1990 to 11.9ºC in 2014

2.5 Related study on Land Cover Change and Land Surface Temperature over the world

In the study of “Effect of land use/cover change on land surface temperature – the Nile Delta, Egypt” Mohamed E.Hereher used a 15 years of bi-monthly Normalized Different Vegetation Index (NDVI) data set acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra satellite The results indicate that mean LST change was determined for each location before and after the land use change Results indicate that NDVI composite data for 15 years proved sufficient for delineating land use change Significant spatial changes include the transformation from agriculture to urban land, which increased the LST by 1.7 °C during the 13 years and the transformation of bare land to agriculture, which decreased the LST by 0.52 °C for the same period Due to the explosive population growth in the Nile Delta, urban encroachment upon agricultural land could, hence, promote a prolonged regional warming by modifying the micro-climate and other climate-related phenomena (E.Hereher, 2017) Meanwhile, the surrounding area of National Botanic Garden, reasearch conducted by a group of author from Faculty of Architecture ,Planning and Serving in Malaysia concluded that there have been significant decreased in the forest and agricultures areas Land Surface Temperature and thermal signal of built-up areas and barren land has increased the radiant temperature.The vegetative areas can provide positive impacts on regulating high temperature in urban areas (Siti Nor Afzan et al.,2013) By contrast, some studies have shown that the land use/land cover alteration are generally caused by mismanagement of agricultural, urban and forest land which leads to severe environmental problems It has been a combination of climatic and economic factors in the study area (Lolab watershed) which has been responsible for

the land use land cover change to take place The methodology adopted for this study

is based upon interpretation of IRS-1C LISS III (FCC) having a resolution of 23.5 mts using standard visual/digital interpretation techniques The data were Georefrenced and as such matched to a standard SOI toposheet of 1:50000 scale The source material was collected from published and unpublished records of various state government departments, especially Directorate of Economics and Statistics, J & K Forest Department, Directorate of Ecology, Environment and Remote Sensing, Soil Conservation Department etc (Shafiq M et al.,2017)

In the study of “Monitoring of Spatio-Temporal Changes in part of Kosi River Basin, Bihar, India Using Remote Sensing and Geographical Information System”, by

a group of professors from India revealed that the utilization of multitemporal satellite datasets for detection and monitoring of changes in the surface water configurations Continuous monitoring of both satellite-generated data and ground patterns of surface water is required for better management The present images helped to identify the trend of spatio-temporal changes of dynamic water configurations in the study area (C Sudhakar et al.,2008).Another paper from Department of Geography and Meteorology, Nnamdi Azikiwe University, Awka, Nigeria, this paper is aimed at identifying the land use/cover types in Awka Town,Nigeria in relation to their temporal dynamics, the extent of land use change in the city and effects of land use change on surface temperature Multitemporal Landsat TM, ETM+ and OLI imageries were obtained at

15 years interval for 1986, 2000 and 2015 respectively The thermal infrared band is converted to at spectral radiance and brightness temperature As reported in similar studies, it is quite clear that the highest values of Land Surface Temperature (LST) are

in the urban or built-up area and other impervious surfaces while the lower LST values

are found around the riparian and dense vegetated areas of Awka The observed changes in the identified land use/cover types of Awka advocate that urbanization is an important factor responsible for land conversion in the study area The increase in rate

of land use change has its attendant effects on both the environment and the comfort of residents This has been monitored by various studies using Landsat ETM+ and TM images (Nzoiwu et al.,2017)

PART III METHOD 3.1 Materials & Data

3.1.1 Data Used

United States Geological Survey (USGS) provided the primary data of five Landsat images with the spatial resolution of 30meters Those are four Landsat 5 Thematic Mapper(TM) images and one Landsat 8 Thermal Infrared Sensor acquired

on clear cloud days in dry season 1998,2004,2008,2010 and 2017 The data used were the available with less cloud cover (below 10%) during dry season in Ho Chi Minh City throughtout the months of January to March Datasets from 1998, 2004, 2008,

2010 and 2017 were used to validate Land Surface Temperature, while data of 1998,

2008 and 2017 were applied to analysis current LULC with a specific focus on urban expansion area

Table 1 Description of the satellite images used in study

Image Quality Landsat 5

utilized to classify land cover type as well as visualize the relationship between land cover change and land surface temperature

ERDAS IMAGINE is an image processing software package that allows users

to process both geospatial and other imagery as well as vector data ERDAS can also handle hyperspectral imagery and LiDAR from various sensors ERDAS also offers a 3D viewing module (VirtualGIS) and a vector module for modeling

3.2 The objectives and the scope

3.2.1 The objects

(1) The land cover change map of Ho Chi Minh City in 1998, 2008 and 2017

- Change Detection map from 1998 to 2017

(2) The Land Surface Temperature map of Ho Chi Minh City in 1998, 2008 and

2017

- Normalized Difference Vegetation Index (NDVI) Map of 1998, 2008 and 2017

- Green Vegetation Fraction Maps of 1998, 2008 and 2017

- Emissivity Map of 1998, 2008 and 2017

- Brightness Temperature Map of 1998, 2008 and 2017

(3).The graph/charts show the relationship between Land Cover Changes and Land Surface Temperature in Ho Chi Minh City during the year 1998, 2008 and 2017

Change Detection Analysis

The impact of Land Cover Change on Land Surface Temperature in HCM from 1998 - 2017

3.3.1 Image Pre-Processing

Image pre-processing is one of the most important steps in analyzing remote sensing data Before performing the main processes, pre-processing of the data to be used were required to be done Correction, compressing and cutting the data to its designed boundary were some of the required steps Figured 3 illustrates the flow chart of the image pre-processing methods

Figure 3 Method for Pre-Processing of remote sensing data

Add TM Bands OLI/TIRS Bands

Layer Stacking

Landsat TM Images Landsat OLI/TIRS Images

Resample Images

Geometric Correction

Study Area Clip

Image Subset

3.3.2 Layer Stacking

LANSAT 5 TM data for 1998 and 2008 and also LANDSAT 8 OLI/TIRS have been obtained from US Geological Survey (USGS) Afterwards, one-band per images files which then layer stacked to combine the bands making it a one multi-band image Landsat 5 TM consists of seven bands while Landsat 8 is comprised of eleven bands presented in Table 2 and Table 3

Table 2 Detail of Landsat 5-TM Satellite Imageries

Band Number Spectral Range µm Spatial Resolution(m) Band Name

Table 3 Details of Landsat 5 –TM Satellite Images

Source: http://landsat.gsfc.nasa.gov/landsat-data-continuity-mission

As can be seen from Table 1, LANSAT 5 acquired January,1998 and March 2008 were layer stacked using the layers 1,2,3,4,5 and 7 in ascending order,due to layer 6 is different spatial resolution while LANDSAT 8 acquired February , 2017 were stacked together using bands 1,2,3,4,5,6,7 and 9 respectively (because of band 8, 10 and 11 are different spatial resolution) These data were imported in ERDAS 2014 to combine two landsat images as Figured 4 below shown

Band Number Spectral Range µm Resolution(m) Spatial Band Name

3.3.3 Image Subset

Clipping or cutting Landsat images to a particular boundary was done in this

research in order to emphasize the study area and to make it easier to examine and evaluate Landsat 5 TM and Landsat 8 OLI/TIRS layer stacked and geometrically corrected images were cut to its boundary , Ho Chi Minh City with its actual shape Figure 5 shows the study areas for three specific years 1998, 2008 and 2017

Figure 5 Clip Area of Ho Chi Minh City for 1998,2008 and 2017

3.3.4 Image Classification and Accuracy Assessment

In order to detect the changes in land use during the period of the study , Land Use Land Cover is essential to study the effects of human actions on a regional scale Landsat images mapped LULC changes for 1998,2008 and 2017 Urban area, water , bare soil and vegetation are the four selected LULC types The images were analyzed according to their spectral profiles so that training sites could be developed , based on ancillary information and reference data from various sources This study designated

50 trainning sample of 100 pixels for each land cover class

The statistical characteristics of the land cover categories were developed once training sites were digitized Landsat images classified by utilizing the maximum likelihood algorithm with a supervised signature extraction The three classified maps were assessed on accuracy by stratified random sampling methods From each LULC class , fifty sample were chose

Table 4 Land cover classification scheme

Urban Built-up land, rural residential, commercial and

services, industrial,transportation

Mixed urban and built-up land

Water Lakes, rivers, streams, reservoirs,canals Vegetation Cultivated land, forest land, grass land

Bare soil Sandy land, dry salt flats, bare exposed rock, strip

mines

Source: https://pubs.usgs.gov/pp/0964/report.pdf

3.3.5 Land Cover Change

Land cover change for the years 1998,2008 and 2017 were done using Landsat Images obtained from USGS’s official website and GIS technology which also has already undergoes the processing data In addition , to distinguish how obvious was the change of HCMC from its previous year to the recent year

3.4.5.1 Training sample selection

There are two types of classification:Unsupervised and Supervised

Classification.Unsupervised classification is where the grouping of pixels are based on the reading of the software The software analyzed the data even without the help of the user providing the same classes On the other hand, Supervised Classification uses training samples by selecting several similar pixels in order to identify each of the land cover types in the study area In this study , supervised classification was used In term