Characteristics of aerosol distribution in spatial and temporal using modis data around hanoi

ii THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY LE HOAI LY CHARACTERISTICS OF AEROSOL DISTRIBUTION IN SPATIAL AND TEMPORAL USING MODIS DATA AROUND HANOI BACHELOR THESIS Study mode Ful[.]

THAI NGUYEN UNIVERSITY

UNIVERSITY OF AGRICULTURE AND FORESTRY

LE HOAI LY CHARACTERISTICS OF AEROSOL DISTRIBUTION IN SPATIAL AND

TEMPORAL USING MODIS DATA AROUND HANOI

BACHELOR THESIS

Study mode : Full-time

Major : Environmental science and management

Faculty : Advanced Education Program

Batch : K46-N01

Thai Nguyen, September 2018

DOCUMENTATION PAGE WITH ABSTRACT

Thai Nguyen University of Agriculture and Forestry

Degree Program Bachelor of Environmental Science and Management

Student name LE HOAI LY

a given region throughout the year In this study, ten years (2009-2018) of AOD observations from the MODIS over 7 areas around HANOI city have been analyzed for atmospheric aerosol loading and particulate matter in air quality assessments on surface level The results showed that the spatial distribution of aerosol was largely affected by topography local economic activities and operation of factories and industrial zones Heavy aerosol loading and increasing tendency in AOD were observed in QUẢNG NINH, HẢI PHÒNG, HẢI DƯƠNG, THÁI BÌNH cities (in Area 4) and HÀ NỘI city (in area 1), while a reverse tendency was revealed in the other regions The spatial distribution of aerosol Angstrom wavelength exponent was predominantly related to vegetation coverage in this areas Airborne dust from ground is an important source of coarse mode aerosols Moreover, the overall AOD changes in areas showed a downward trend during the past 10 years, suggesting that environmental remediation measures have achieved initial improvements The trend of seasonal changes indicated that the AOD values were highest in the springtime, and slightly higher in the wintertime, which are significantly higher than the summer and the autumn seasons For the temporal variation, the maximum of AOD values during certain periods gradually increase from 2009 to 2013, and the maximum of AOD values during certain periods gradually decrease from 2014 to 2018 and types of pollutants

ACKNOWLEDGEMENT

To complete this thesis, I would like to express my deep gratitude to Professor Tang-Huang Lin took time out to hear, guide, help me complete my report during the time of conducting the research at Center for Space and Remote Sensing Research (CSRSR) of National Central University (NCU)

I aslo would like to send my sincere thanks to the teachers of the TN University Agr & Forestry, especially my teacher, Associate Professor Doctor Dam Xuan Van, transmited knowledge in the years of study The knowledge acquired during the learning process is not only the foundation for me to do the research process but also the way to get into life With limited knowledge, in the practice and perfecting this thesis, I can not avoid mistakes,

I hope to receive comments from teachers!

In the end, I wish teachers good health, success in cause and life!

Thai Nguyen, December 2018

Table of Contents

PART I INTRODUCTION 1

1.1 Research rationale 1

1.2 Research’s questions 5

1.3 Limitations 5

1.4 The requirement 5

PART II LITERATURE REVIEW 7

2.1 Aerosol 7

2.1.1 Aerosol and the function of aerosol in the environment 7

2.1.2 Effect of aerosol on human health 8

2.2 Aerosol optical depth (AOD) 9

2.3 MODIS 11

2.4 The role of aerosol types 13

2.5 Using MATLAB and Excel software 14

PART III DATA AND METHODOLOGY 18

3.1 Study area 18

3.2 Dataset and Analyses 20

3.3 Methodology 24

PART IV RESULT AND DISCUSSION 28

4.1 Temporal 28

4.1.1 Diurnal: Morning - Terra (MOD) data in MODIS and Afternoon - Aqua (MYD) data in MODIS 28

4.1.3 Annual (10 years 2009-2018) 32

The AOD tends to decrease year by year, demonstrating that people are aware of importance and protection the environmental, although AOD is still high 33

4.2 Spatial (7 areas) 33

4.3 Distribution type of aerosol 38

PART V CONCLUSION AND SUGGESSION 39

5.1 Conclusion 39

5.2 Suggession 40

REFERENCES 41

LIST OF FIGURES

Figure 1: The average monthly aerosol amounts around the world based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra

satellite 15

Figure 2: The picture of 7 areas around HANOI in the Earth 24

Figure 3: The image of 7 areas around HANOI in MODIS 25

Figure 4: The flowchart of analysis procedure 33

Figure 5: Time series of diurnal mean MODIS AOD averaged in 7 areas over 10 year Vertical bar shows average values Blue and orange line present the values of the morning and afternoon respectively 34

Figure 6: Seasonal mean distribution of the aerosol optical depth (AOD) over 7 areas in winter(blue line), spring (oranges line) , summer (gray line), and autumn (yellow line) 35

Figure 7: Distribution of AOD for 4 seasons in 10 years 36

Figure 8: Annual variation of AOD between 2009 and 2018 over 7 areas 38

Figure 9: The mean variation of AOD in 10 years 39

Figure 10: Mean trend in aerosol optical depths on Area 1 in 10 years 39

Figure 11: Mean trend in aerosol optical depths on Area 7 in 10 years 40

Figure 12: Mean trend in aerosol optical depths on Area 6 in 10 years 40

Figure 13: Mean trend in aerosol optical depths on Area 5 in 10 years 41

Figure 14: Mean trend in aerosol optical depths on Area 4 in 10 years 41

Figure 15: Mean trend in aerosol optical depths on Area 3 in 10 years 42

Figure 16: Mean trend in aerosol optical depths on Area 2 in 10 years 42

Figure 17: frequency distribution type of aerosol in each areas 44

LIST OF TABLES

Table 1 Geographical information 25

Table 2: The average AOD in regions over 10 years 28

Table 3: The AOD average data for 4 seasons in each area 28

Table 4: The AOD average data for 4 seasons in 10 years 29

Table 5: Aerosol type classification from MODIS data 29

Table 6: The frequency distribution of type pollution 30

Table 7: Seasonal in Việt Nam 35

LIST OF ABBREVIATION

AOD Aerosol Optical Depth

MODIS Moderate Resolution Imaging Spectroradiometer NASA National Aeronautics and Space Administration AOT Aerosol Optical Thickness

DS Dust

AP Anthropogenic pollutant

BB Biomass Burning

PART I INTRODUCTION

1.1 Research rationale

Nowadays, the problem of air pollution, especially in urban areas, was not only a

problem of a country or a area but also became a global problem Recently, the

socio-economic development of countries in the world has had a great impact on the

environment which has made the human environment change and become worse In

recent years, human has paid much attention to the problem of air pollution: climate

change and global warming, ozone depletion and acid rain In HANOI, air pollution is

a pressing issue for the urban environment, industry and trade villages

Impact of air pollution on human health: Air pollution has a great impact on health

When the air environment is polluted, human health is getting deteriorated, the aging

process in the body occurs rapidly; The function of respiratory system is declined,

causing asthma, bronchitis, cardiovascular disease and reducing the human

longevity etc The most sensitive community groups with air pollution are the

elderly, pregnant women, children under 14 years of age, people who are sick, workers

who work outdoors and so forth

Air pollution has a negative impact on human health, especially causing respiratory

diseases Especially in the Hanoi capital are facing the problem of heavy air pollution

In industrial parks, the roads are polluted at different levels, the concentration of

pollutants exceeds the permitted standards making the pollution situation become

serious

Aerosol, consisting of a variety of tiny solid and liquid particles suspended in the

atmosphere Windblown dust, sea salts, volcanic ash, smoke from wildfires, and

pollution from factories are all examples of aerosols Depending upon their size, type,

and location, aerosols can either cool the surface, or warm it They can help clouds to

form, or they can inhibit cloud formation And if inhaled, some aerosols can be

harmful to people's health Aerosol may directly impact the earth’s energy budget by scattering and absorbing solar radiation, altering the radiative balance of the earth-

atmosphere system, and indirectly by acting as cloud condensation nuclei and ice

nuclei, thus modifying the microphysical properties and lifetime of clouds, and hence

their radiative characteristics

Interactions between aerosols and clouds have become the subject of scientific

research because of the importance of clouds in controlling climate (Mahowald and

Kiehl,2003) Aerosols show both temporal and spatial variations, which can lead to

variations in the optical properties of clouds Atmospheric aerosol particles generally

have variable diameters They may be either directly emitted into the atmosphere, or

formed by the oxidation of precursor gases, such as certain oxides or volatile organic

compounds, where the resulting oxidation products eithernucleate to form new

particles or condense on pre-existing ones Particles formed through these two routes

are irecteffects of aerosols on cloud parameters and compared modeled results with

MODIS data Due to the large spatial and temporal extent of aerosols (dust, pollution,

etc.) in the atmosphere (Rosenfeld,2001), the interactions between aerosols and clouds

can have substantial climatic impacts This research focused on the main objectives It

was to investigate the seasonal, temporal and spatial variations of MODIS AOD over

various cities around HANOI, including research into theorigins of those air masses

bringing aerosol particles to the vicinity of HANOI

The instruments aboard NASA's Terra and Aqua satellites have been observing the

Earth since early 2000 and mid‐2002, respectively,one of the instruments aboard

both Terra and Aqua used to characterize atmospheric aerosols is the Moderate

Resolution Imaging Spectroradiometer (MODIS) In the words of Dr Yoram J

Kaufman, Terra Project Scientist at the time of the Terra launch, the Terra and Aqua

missions were “designed for a comprehensive check‐up of planet Earth” (Y J

Kaufman, http://terra.nasa.gov/Events/FirstImages/, 2000) Similar to a checkup at the

doctor's office, these missions would characterize the health of the planet The goal

was to use the vantage point of space to view the Earth's interconnected systems of

atmosphere, land and ocean, and to characterize the parameters important to the

sustainability of the planet and its human population

One important feature measured by several instruments aboard Terra and Aqua is

atmospheric aerosol These small solid or liquid particles suspended in the atmosphere

play a major role in the energy balance of the Earth, in modifying cloud, precipitation,

and atmospheric circulation characteristics, in providing nutrients to nutrient‐limited

regions of land and oceans, and in affecting air quality and public health Aerosols are

highly inhomogeneous in space, time and composition, and yet, knowing the amount,

composition, distribution, size and shape of these particles is necessary for any

meaningful estimates of their effect, from estimating anthropogenic climate forcing to

forecasting air quality and potential health effects from air pollution

The average monthly aerosol amounts around the world based on observations from

the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's satellite

The most common parameter derived from satellite observations is the Aerosol Optical

Depth (AOD) AOD is the key factor to calculate the content of the aerosol, evaluating

the conditions of the atmosphere and the effect of atmosphere aerosol on climate It is

important for the research of haze and atmospheric correction It can also indicate air

turbidity to a certain extent, and is an important parameter in the quantitative

calculation of aerosol radiative forcing The AOD is usually obtained from

ground-based and space-ground-based observations

1.2 Research’s objectives

Using AOD to calculate the content of the aerosol, evaluating the conditions of the

atmosphere and the effect of atmosphere aerosol on climate

This research focused on the main objectives It was to investigate the seasonal,

temporal and spatial variations of MODIS AOD over various cities around HANOI,

including research into the origins of those air masses bringing aerosol particles to the

vicinity of HANOI

1.3 Research’s questions

1 How does the aerosol affect geographical regions?

2 How has the aerosol changed over the years?

3 How does aerosols affect air quality through satellite observations?

4 How does the distribution of pollutant types occur in regions?

1.4 Limitations

However, the data processing on satellite still has obvious limitations when coverage

is obscured by clouds In addition, there exists a spindly scanning gap around the

equator between two contiguous satellite orbits, because the scanning swath

(approximate 2330 km) is not wide enough to completely cover low-latitude regions

Since satellite AOD products from different sensors have different uncertainties and

cannot provide consistent measurements, it is reasonable to take advantage of

multi-temporal recovery by using MODIS AOD from the morning satellite Terra and

afternoon satellite Aqua

1.5 The requirement

1 Acquiring AOD from ground measurement

2 Collecting AOD data from seven ground based stations:

A1: HaNoi city

A2: Thanh Hóa province

A3: Nghệ An province

A4: Industrial areas (Quảng Ninh, Hải Phòng, Hải Dương)

A5: Hà Giang province (mountain area)

A6: Cao Bằng province (Mountainous forests take up more than 90% of the province)

A7: Lạng Sơn

PART II LITERATURE REVIEW

2.1 Aerosol

2.1.1 Aerosol and the function of aerosol in the environment

The impact of atmospheric aerosols on the earth’s climate system is poorly understood, and is a subject of considerable interest for the scientific community as

well as policy makers (Kaufman et al., 2002) Aerosols are not only emitted directly

into the atmosphere by anthropogenic and natural sources, but are also formed in the

atmosphere through various physical and chemical processes (Seinfeld and Pandis,

2006) They impact the climate system by absorbing and reflecting solar radiation and

modifying cloud properties Aerosols are also referred to as particulate matter (PM),

and human exposure to them is known to cause serious damage to human health (Pope

et al., 2009)

Since the increase of urbanization, atmospheric particles have become one of the

most important factors influencing urban air pollution As global economic growth

increases, environmental pollution becomes increasingly more serious It is known

that the physics, chemistry, and optical characteristics of atmospheric aerosols are

closely related to homogeneous- and heterogeneous-phase chemical reactions, which

result in a series of environment problems, including air quality degradation, ozone

layer destruction, acid rain formation, and smoke-fog related accidents Aerosol

particles are intuitive atmospheric trace components that can be detected by the senses;

they interfere with the visual field and are harmful for the respiratory systems of

animals and mankind (Dockery et al., 1993; Garshick et al., 2008; Ramon et al., 2006;

Pope, 2000; Schichtel et al., 2001; Schwartz et al., 1996; Tsai et al., 2003; Tsai and

Cheng, 1999; Wilson and Suh, 1997) Atmospheric aerosol pollution can be serious,

and there has been an increase of serious accidents resulting from aerosol pollution

(Dockery et al., 1993; Schichtel et al., 2001) The aerosols in polluted urban air usually

contain many complex organic chemicals, such as volatile organic compounds

(VOCs), polycyclic aromatic hydrocarbons (PAHs), fumigants, and agricultural

chemicals (Cheng et al., 2007; Bi et al., 2005; Fang et al., 2005; Hong et al., 2007; De

Kok et al., 2006; Miyazaki et al., 2009; Mastral et al., 2003; Uchimiya et al., 2008;

Wang et al., 2007; Wingfors et al., 2001; Xie et al., 2009; Yassa et al., 2001) These

chemicals have specific physiological impacts on human health Therefore, aerosols

are closely connected to human existence

2.1.2 Effect of aerosol on human health

Aerosols are small solid or liquid particles suspended in the air From a climate

standpoint aerosols are important because they can alter the planetary radiation

balance Unlike greenhouse gases that have long atmospheric residence times, aerosols

are generally removed in days Thus, their distribution tends to be heterogeneous, with

larger aerosol concentrations near their sources This means that the climate forcing

due to aerosols is highly regional Aerosols have both natural and anthropogenic

sources Examples of natural sources of aerosols are wind-blown desert dust, and sea

salt Anthropogenic aerosols tend to be associated with combustion by-products

Examples of anthropogenic aerosols are sulfates and nitrates In addition to their role

in climate, aerosols are also of interest because they decrease visibility, contribute

to acid rain, and can affect human health Numerous international studies have looked

at the relationship between aerosols and increased mortality According to a recent

international Commonwealth Science Council conference, air pollution kills eight

thousand people every day worldwide

2.2 Aerosol optical depth (AOD)

Figure 1: The average monthly aerosol amounts around the world based on

observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on

NASA's Terra satellite

In the air pollution monitoring applications, Aerosol Optical Thickness/Aerosol

Optical Depth (AOT/AOD) is considered as one of the Essential Climate Variables

(ECV) that influences climate, visibility and quality of the air Satellite derived AOD

is representative for the amount of particulates in a vertical column of the Earth’s atmosphere Aerosol concentration can be measured directly by ground based

sunphotometer or estimated by sensors onboard satellites Ground measurements have

high accuracy and temporal frequency but they are representative of a limited spatial

range around station Conversely, satellite data provide aerosol at larger scale with

moderate quality and lower frequency,see also Figure 1 Recently, the accuracy of

satellite derived aerosol has been increasing and show an acceptable quality in

comparison with ground based aerosol measurement

Mass concentration quantification by an optical measure known aerosol optical

depth (AOD) is usually used to estimate the aerosol loading or amount in the

atmosphere Various scientific researchers have been recognized that atmospheric

aerosol is a key parameter in climate change studies especially over South Asia

Atmospheric temperature fluctuations, radiative forcing, rainfall pattern changes,

intensive tropical cyclone and desertification are examined by aerosol studies

Aerosols exhibit high spatial-temporal variations which influence the cloud properties

and precipitation processes These indirect effects are recognized by several literatures

on regional and global scale Satellite data is important and useful for the study about

air quality research Satellite retrievals of column aerosol optical depth (AOD) are a

cost effective way to monitor and study aerosols distribution and effects on climate

reported that for mapping the distribution and properties of aerosols satellite data has

tremendous potential Due to sparse of ground measurements in many regions of the

world satellite data is the only way to monitoring aerosol loads and aerosol properties

in a regional and global scare

2.3 MODIS

MODIS onboard the two EOS Terra and Aqua satellites, has been providing AOD

retrievals for more than 11 years, twice daily (under cloud free conditions) on a near–

global basis with high spatial resolution (10 km2) with good accuracy over dark

vegetated surfaces (Levy et al., 2010) The quality of the MODIS AOD retrievals

decreases when the underlying surface becomes bright and/or heterogeneous; these

conditions are typically found in desert and urban regions (Levy et al., 2010) Proper

sampling of satellite AOD over a region is very important for correctly characterizing

aerosol properties over the area of interest (Levy et al., 2009; Sayer et al., 2010) It is

often convenient to utilize Level 3 gridded daily, weekly, or monthly mean products

to analyze long– term trends and climate implications However, Levy et al (2009)

have shown that different choices for aggregation and weighting result in estimates of

global/regional means of MODIS AOD that differ by 30% or more Levy et al (2009)

recommended that one must consider the spatial and temporal density of the

measurements relative to the gradients of the true AOD, and that only retrievals of the

highest quality should be utilized

Satellite-derived AOD fills this vacancy with spatially continuous observations,

providing better spatial and temporal coverage for regional assessments on a large

scale cloud particle size from Aqua MODIS can be used to examine the aerosol

indirect effect Changes of cloud particle size due to aerosols are important

information for climate studies, and for understanding the response of the climate

system to changes in air pollution

In this study, ten years of MODIS Terra aerosol optical depth data is utilized to

examine the atmospheric aerosols loading over seven urban regions around HANOI

Area 1 and area 4 are largest and the second largest populated urban areas in the

country with very high levels of surface pollution The human and vehicular

population of area 1 is about 8 million whereas about 4 million people lives in area 4

Two types of MODIS data will be used in this paper: Level 2 (L2) and Level 3 (L3)

MODIS L2 aerosol data are ungridded 10 km retrievals of various aerosol parameters

available at the time of satellite overpass These data represent the fundamental

MODIS aerosol product The product consists of geophysical parameters such as

aerosol optical depth and aerosol particle size information, as well as a quality

assurance (QA) flag that indicates the level of reliability of each retrieval QA flags

range from 0 (lowest quality) to 3 (highest quality) Comparison of the L2 data,

collocated in time and location with high‐quality ground measurements provide the

“validation” of the basic product

MODIS L3 data are an aggregation of the L2 data onto a gridded 1° × 1° global grid

and represent the statistics including the mean and weighted means of the L2 product

contained within the grid square L3 data are available on a daily basis The daily L3

data are further aggregated to create L3 monthly means, also on a 1° × 1° global grid

The global gridded data of L3 will provide the basic set of data for the climatology

presented here

Various studies have used MODIS level 3 gridded one degree resolution AOD

products to analyze long–term trends in atmospheric aerosol loadings and estimates of

radiative forcing over urban centers As documented elsewhere, retrieval of AOD from

MODIS becomes challenging and more uncertain over regions with high surface

reflectance and complex mixture of aerosols The primary objective of this study is to

examine whether the quality of MODIS AOD retrievals over 7 areas is adequate for

air quality and climate applications The second objective is to document whether

spatial and temporal trends are present in the available MODIS AOD data in this

region, providing recommendation for future research

2.4 The role of aerosol types

Aerosol types have complex properties such as tiny size particle (micro and

submicron) and different in phases (liquid or solid) that are suspended in the

atmosphere (Balarabe et al., 2016) Depending upon their shapes, sizes and

composition they can reflect sunlight back to space and cool the atmosphere, they

can also absorb sunlight and warm the atmosphere Aerosols can even change the

lifetimes of clouds, how much rainfall can occur, and how they reflect sunlight They

further can enable chemical reactions to occur on Because cloud droplets form on

aerosol particles, changes in aerosol concentration and properties can alter cloud

properties and precipitation There are many sources of aerosols both natural and

resulting from human activities with widely varying distribution and properties

Mineral dust consists of large, non-spherical particles that absorb UV radiation due

mainly to their iron oxide content Fresh smoke from forest, agricultural, or

grassland fires mainly consists of small particles that absorb light in the UV and

visible range (Dubovik et al., 2002)

In this study, the characteristics of aerosol types from AERONET is analyzed

on a global scale to determine the dominant aerosol type at each location, which

established thresholds for Dust, Biomass burning and Anthropogenic pollutant,

especially it has been successfully classified mix - aerosols (dust and biomass

burning, biomass burning and anthropogenic pollutant) as shown in table 5

The extinction of sunlight by aerosols when it passes vertically through the

atmosphere from the top of the atmosphere to the surface is called the aerosol optical

depth (τa) In general, the optical properties of aerosols are the functions of wavelength, and the spectral variance in radiometry may be inconsistent between

types of aerosols

Three kinds of dual-type aerosols are classified including AP mixed with BB

aerosols (APBB), Dust mixed with BB aerosols (DustBB) and Dust mixed with AP

aerosols (DustAP)

2.5 Using MATLAB and Excel software

MATLAB, which stands for MATrix LABoratory, is a state-of-the-art mathematical

software package, which is used extensively in both academia and industry It is an

interactive program for numerical computation and data visualization, which along

with its programming capabilities provides a very useful tool for almost all areas of

science and engineering Unlike other mathematical packages, such as MAPLE or

MATHEMATICA, MATLAB cannot perform symbolic manipulations without the

use of additional Toolboxes It remains however, one of the leading software packages

for numerical computation As you might guess from its name, MATLAB deals mainly

with matrices A scalar is a 1 matrix and a row vector of length say 5, is a

1-by-5 matrix We will elaborate more on these and other features of MATLAB in the

sections that follow One of the many advantages of MATLAB is the natural notation

used It looks a lot like the notation that you encounter in a linear algebra course This

makes the use of the program especially easy and it is what makes MATLAB a natural

choice for numerical computations

MATLAB is a programming language developed by Math Works It started out as

a matrix programming language where linear algebra programming was simple It can

be run both under interactive sessions and as a batch job MATLAB (matrix

laboratory) is a fourth-generation high-level programming language and interactive

environment for numerical computation, visualization and programming It allows

matrix manipulations; plotting of functions and data; implementation of algorithms;

creation of user interfaces; interfacing with programs written in other languages,

including C, C++, Java, and FORTRAN; analyze data; develop algorithms; and create

models and applications It has numerous built-in commands and math functions that

help you in mathematical calculations, generating plots, and performing numerical

methods

Following are the basic features of MATLAB:

- It is a high-level language for numerical computation, visualization and

application development

- It also provides an interactive environment for iterative exploration, design and

problem solving

- It provides vast library of mathematical functions for linear algebra, statistics,

Fourier analysis, filtering, optimization, numerical integration and solving ordinary

differential equations

- It provides built-in graphics for visualizing data and tools for creating custom

plots MATLAB's programming interface gives development tools for improving code

quality, maintainability, and maximizing performance

- It provides tools for building applications with custom graphical interfaces

- It provides functions for integrating MATLAB based algorithms with external

applications and languages such as C, Java, NET and Microsoft Excel

MATLAB is widely used as a computational tool in science and engineering

encompassing the fields of physics, chemistry, math and all engineering streams It is

used in a range of applications including: signal processing and Communications

image and video Processing, control systems, test and measurement, computational

finance, computational biology

Matlab and excel software were used to handle and analyze all satellite aerosols,

classified aerosol types