Boundary-layer height detection with a ceilometer at a coastal ... - Orbit
Boundary-layer height detection with a ceilometer at a coastal ... - Orbit
Boundary-layer height detection with a ceilometer at a coastal ... - Orbit
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Contents<br />
1 Introduction 5<br />
1.1 Thesis contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6<br />
2 Theory 7<br />
2.1 Introduction to the <strong>at</strong>mospheric boundary <strong>layer</strong> . . . . . . . . . . . . . . . . 7<br />
2.2 Entrainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8<br />
2.3 Flow and scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9<br />
2.4 Turbulence kinetic energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9<br />
2.5 The Obukhov Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10<br />
2.6 The marine boundary <strong>layer</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . 11<br />
2.7 <strong>Boundary</strong>-<strong>layer</strong> clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12<br />
2.8 St<strong>at</strong>istical methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13<br />
3 Site and measurements 16<br />
3.1 Høvsøre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16<br />
3.2 The <strong>ceilometer</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16<br />
3.3 The wind LIDAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17<br />
3.4 Sonic anemometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19<br />
3.5 Instrumental set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20<br />
3.6 The Høvsøre d<strong>at</strong>abase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21<br />
4 <strong>Boundary</strong>-<strong>layer</strong> <strong>height</strong> <strong>detection</strong> 22<br />
4.1 The vertical gradient of the aerosol profile . . . . . . . . . . . . . . . . . . . 22<br />
4.2 Critical threshold value of the aerosol profile . . . . . . . . . . . . . . . . . . 23<br />
4.3 Fitting an idealized aerosol backsc<strong>at</strong>ter profile . . . . . . . . . . . . . . . . . 24<br />
4.4 Addition to the idealized profile . . . . . . . . . . . . . . . . . . . . . . . . . 25<br />
4.5 Filtering clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25<br />
4.6 Minimum turbulence kinetic energy . . . . . . . . . . . . . . . . . . . . . . . 27<br />
5 Results 29<br />
5.1 Clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29<br />
5.2 Continuous and average d<strong>at</strong>a . . . . . . . . . . . . . . . . . . . . . . . . . . 34<br />
5.3 Comparison <strong>with</strong> a wind lidar . . . . . . . . . . . . . . . . . . . . . . . . . . 39<br />
5.4 Cold front passage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44<br />
5.5 Ideal daily evolution of the ABL . . . . . . . . . . . . . . . . . . . . . . . . 47<br />
5.6 Exponent idealized profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49<br />
5.7 Evolution of the CTBL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51<br />
5.8 Frequency distributions of BLH estim<strong>at</strong>es . . . . . . . . . . . . . . . . . . . 55<br />
5.9 Intra-annual vari<strong>at</strong>ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66<br />
6 Discussion 67<br />
7 Conclusion 71<br />
A Appendix 72<br />
B Appendix 73<br />
References 74<br />
4 DTU Wind Energy Master Thesis M-0039
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