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UNIVERSITY OF CALIFORNIA SAN DIEGO The Influence of Meteorology and Cloud Properties on Downwelling Shortwave and Longwave Irradiance at Ross Island, Antarctica A Thesis submitted in partial satisfaction of the requirements for the degree Master of Science in Earth Sciences by Kristopher Scarci Committee in Charge: Dan Lubin, Chair Joel Norris Lynn Russell 2018 Copyright Kristopher Scarci, 2018 All Rights Reserved. The thesis of Kristopher Scarci is approved, and it is acceptable in the quality and form for publication on microfilm and electronically: Chair University of California San Diego 2018 iii TABLE OF CONTENTS Signature Page ............................................................................................................................................................................................iii Table of Contents .......................................................................................................................................................................................iv List of Figures ...............................................................................................................................................................................................v List of Acronyms .................................................................................................................................................................................vi-vii Acknowledgments...................................................................................................................................................................................viii Abstract of the Thesis ..........................................................................................................................................................................ix-x 1. Introduction .............................................................................................................................................................................................1 1.1 AWARE Campaign …..........................................................................................................................................................1 1.2 Area of Study ........................................................................................................................................................................4 2. Site Representativeness …...................................................................................................................................................................6 2.1 Cloud Radiative Effect .......................................................................................................................................................6 2.2 Examples of Data ….............................................................................................................................................................7 2.3 AWS Stations .........................................................................................................................................................................7 3. Methodology ...........................................................................................................................................................................................10 3.1 k-means Clustering Algorithm ....................................................................................................................................10 3.2 Regime Classifications ....................................................................................................................................................11 3.3 Regime 4 & the Ross Ice Shelf Airstream (RAS)...................................................................................................14 3.4 Instruments ........................................................................................................................................................................15 3.5 Example Days from Each Regime...............................................................................................................................19 3.6 Cloud Cover & Broadband Atmospheric Transmission …................................................................................20 3.7 Influence of Cloud Phase on Cloud Optical Depth...............................................................................................25 4. Results .......................................................................................................................................................................................................30 4.1 Regime Comparisons ......................................................................................................................................................30 4.2 Regime 1 & 2 .......................................................................................................................................................................31 4.3 Regime 1 & 4 .......................................................................................................................................................................32 4.4 Regime 2 & 4 .......................................................................................................................................................................33 5. Discussion ................................................................................................................................................................................................34 5.1 Supplemental Ice Water Absorption ........................................................................................................................34 5.2 Synoptic Meteorological Drivers & SAM Connection .......................................................................................35 6. Conclusion ...............................................................................................................................................................................................37 Figure Appendix ........................................................................................................................................................................................39 References ....................................................................................................................................................................................................63 iv LIST OF FIGURES Figure 1: CRE Examples a. 10-DEC-2015..................................................................................................................................................39 b. 11-JAN-2016...................................................................................................................................................40 Figure 2: AWS Station Map.........................................................................................................................................41 Figure 3: AWS Decadal Temperature Averages Boxplots..............................................................................42 Figure 4: ERA-Interim Reanalysis Z700 Composite........................................................................................43 Figure 5: ERA-Interim Reanalysis T2M Composite with AWS Temperature Anomaly Overlay............................................................................................................................................44 Figure 6: Regime Sorted Days via k-means-Clustering Algorithm….......................................................45 Figure 7: ARSCL/KAZR/MPL Plots of Example Day for Each Regime…..................................................46 Figure 8: Narrowband Albedo Time-Series.........................................................................................................47 Figure 9: Narrowband Transmission vs Broadband Transmission Plot.................................................48 Figure 10: Narrowband Transmission vs Broadband Transmission Plot (Zoomed) ........................48 Figure 11: Cloud Optical Depth Distributions – Number of Observations ............................................49 Figure 12: Cloud Optical Depth Distributions – Frequency of Occurrence ...........................................50 Figure 13: Regime 1 & 2 Shortwave Comparisons ….......................................................................................51 Figure 14: Regime 1 & 2 Shortwave Differences & t-Statistic ….................................................................52 Figure 15: Regime 1 & 4 Shortwave Comparisons ….......................................................................................53 Figure 16: Regime 1 & 4 Shortwave Differences & t-Statistic ….................................................................54 Figure 17: Regime 2 & 4 Shortwave Comparisons ….......................................................................................55 Figure 18: Regime 2 & 4 Shortwave Differences & t-Statistic ….................................................................56 Figure 19: Regime Shortwave Differences Summary Results ....................................................................57 Figure 20: Regime Longwave Comparisons..…...................................................................................................58 Figure 21: Regime Longwave Differences & t-Statistic..…..............................................................................59