Numerical models for pollutant dispersion in the atmosphere

NUMERICAL MODELS FOR POLLUTANT DISPERSION IN THE ATMOSPHERE

Thesis by

SWATS BASU

Centre for Atmospheric and Fluids Sciences Indian Institrte of T`echnology,New Delhi

Submitted to the Indian Institute of Technology, Delhi for the award of the degree of

DOCTOR OF PHILOSOPHY

19 83'

... to my parents

CERTIFICATE

This is to certify that the thesis entitled

;NUMERICAL MODELS FOR POLLUTANT DISPERSION IN THE ATMOSPHERE"

being submitted by SWATI BASU for the award of the degree of DOCTOR OF PHILOSOPHYi is a record of the original bonafide research work carried out by her. She has worked under our

joint guidance and supervision and has fulfilled the require merits for the submission of this thesis. The results presented in this thesis have not been submitted in part or full to any other University or Institute for award of any degree/diploma.

(N• RAGHAVA N

Senior Planetarium Educator Jawaharlal Nehru Memorial Fund Teen

Murti'

New Delhi.

( o. P. S1 A )

Senior Scientific Officer,I Centre for Atmospheric and

Fluids Sciences

Indian Institute of Technology', New Delhi.

KNOWLEDGEMENTS

I am deeply indebted to Dr. (Mrs.) N. Raghavan under whose supervision I have worked for the last three and a half years* for her painstaking guidance, immense help and constant encouragement throughout this work.

I am also grateful to Dr. O.P. Sharma for his help from time to time.

I am grateful to Professor M.P. Singh who in his

capacity as Head of the Department extended all the necessary facilities and help and encouzgement throughout the duration of this work.

My sincere thanks are due to India Meteoro.Iogical Department for provision of various data which was required

from time to time and also to Department of Science and Technology for sponsoring the project

a.t

I thank Miss Neelam Dhody for her accurate and meticulous typing of the thesis.'

Finally. 7 would like to thank my husband and in—laws without whose cooperation and encouragement it would not have been possible to complete the work.'

csu.

ST ATI BASU

CONTENTS

Page ABSTRACT

CHAPTER T: REVIEW

1.1 Introduction 1

1.2 The Need for PBL Model 2

1.3 Summary of Selected PBL Models 3

1.4'

KM-

(TE) Equation 5

1•S Dispersal of Pollutants 10

1.6 The Coupled Model lz

CHAPTER .1I= ASSUMPTIONS AND FORMULATION

2.1 Introduction 30

2.2 PBL Model Assumptions- 33 2.3 Formulation of Mixing Lengths 35 2.4 Simplification of the Advection 38

Diffusion Equation

2.5 Model Equations and Formulation 41 2.6 Numerical Schemes and Procedure 44

2.7 Input Parameters 48

CHAPTER Il-I: THE NEUTRAL BOUNDARY LAYER

3.1 Introduction 50

3.2 Model Formulation 5*1

3.3 Numerical Experiments 54 3.4 Comparison With Observations 58 3.5 Height_ o.f Maximum Diffusivity 59 3.6 Discussion of Results 60

3.7 Conclusions 65

Pace

CHAPTER _Ij: THE NOCTURNAL BOUNDARY L7YEi .

4.1 Introduction 68

4•:2 Model Formulation 69 4.3 Numerical Experiments 73 4.4 Discussion of Results 78

4.5 Conclusion 82

CHAPTER 'V: CONVECTIVE BOUNDARY LAYER

5.1 Introduction 86

5.2 Model Formulation 89

5.3 Numerical Experiments 92 5.4 Discussion of Results 94

5.5 Conclusion 95

CHAPTER '`'I: THE ADVECTION DIFFUSION MODEL

6.1 Introduction 96

6.2 Assumptions and Formulations 100 6.3; Numerical Experiments 104 6.4 Discussion of ...Results 108

6.5- Conclusions 110

CHAPTER VII: THE COUPLED MODEL

7.1 Introduction 115' 7•'2 Model Formulation 117 7.3' Numerical Experiments 119 7.4 Discussion of Results 127

7.51 Conclusion 131

Pie

CHAPTER VIII. SUGGESTION ' FOR FUTURE ti'dORK.

8.1 Achievements 135

8.2 Future Work Suggested; 136

8.3 Conclusions 136

REFERENCES 140

LIST OF PUBLICATIONS AND PRESENTATIONS 146