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Summer 2013 Blog - Carter Chung

Carter Chung is spending nine weeks in Hong Kong working at the Chinese University of Hong Kong. 

August 16, 2013


My graphs clearly show wind velocity ratio falling with an increase in local frontal area density”, and I have created a preliminary predictive model connecting the two. Thousands of words and a good number of equations and figures later, I have written my first full research paper, ready to be reviewed for submission to journals.

The research experience was very fruitful — in just a summer I have gained a deep understanding of wind, and sharpened my research, statistical analysis, and programming skills. I have learned to work and find answers independently when the answers are not in the back of my textbook — or even in my professor’s.

I’m especially grateful to have been sent to Hong Kong, where just a few years ago, observations of the urban heat island effect led to the very idea of the Cal Energy Corps. There I was able to see, feel, and study for myself the effect the people in our world are having on our world. Not just on the environment, but on the comfort, safety, and well-being of the people. And I am honored to be part of a collective step toward turning that effect positive.

The summer is over, but finding one solution, taking one step has guaranteed me one thing: finding more solutions, taking more steps.
July 23, 2013

Backup Plan


Pictures Carter took while conducting on-site observations of the urban morphology.

Take a one or zero to indicate whether or not there is a building…multiply by wind alignment factor, divide by distance from point of interest…integrate along the radius and in all directions…

Admittedly I was a little nervous to run my tests. If my formula didn’t yield any useful results, where would I go from there? Time was running out, and I needed to get started writing my paper. I started to think of backup plans, and thought about what I would write about if I couldn’t detect any trends. I shook my head. Let’s worry about that after I see if it works. I clicked “run”.

The scatter plot appeared. A few outliers. Okay, all outliers. I tried toggling the radius of interest. The data continued to look randomly generated.

The next day I did what I should have done much earlier. I mapped out wind velocity ratio data for Tsim Sha Tsui district, put it in my bag and hopped on a train down to Tsim Sha Tsui. I spent the morning and afternoon walking to the points where data were taken, and looked around, taking pictures and detailed notes on why the wind might be especially strong or especially weak where I stood.

I noticed a few things. It was clear that I overestimated how important distance from a point was in my calculations. A building 1 meter away does not block 10 times more wind than a building 10 meters away. Much more important than distance to buildings, it appeared, was the direction of openness.

Back in the office, I considered my options. I realized I hadn’t considered the merits of frontal area density within a radius of a point. The area-average method had been proven, why not try? I quickly entered the data, wrote the programs, and clicked “run”.

Well, well. A trend.


July 5, 2013

Missing pieces


Carter and Sofia at a progress meeting with their supervisor.

On my first day here, the professor handed me a box of puzzle pieces. Someone, he explained, had poured 5 different puzzles into a box, shook them up, and threw away two thirds of the pieces. My job would be to reassemble one of the puzzles with the pieces left. As of today I have built a machine to sort puzzle pieces by fit types, one to sort by color, and another to differentiate ocean and sky pieces. I have laid out the pieces neatly into sections on table, and what remains to be done is to try putting the pieces together and hope that the full puzzle is in there.

So that didn’t actually happen. That is, however, where I stand today with the wind project. The data is compiled, the programs are written, and just the analysis is waiting to be done. I’ve also brought the game to my home court: instead of working in ArcGIS, I have imported the data into MATLAB-friendly formats, so I can more efficiently perform a wider range of calculations. Data on paper is now digital. I have now written programs to read and display maps of select areas of Hong Kong, to highlight the points of interest on the map in blue, to look at the morphology within a radius of interest around those points and perform calculations based on those characteristics, and to perform statistical analysis to try and extract meaning out of the data. At this point, the next steps will be a cycle of tweaking parameters, adapting algorithms, reflecting, brainstorming, and repeating. With so many factors affecting wind, including, I suspect, a hint of randomness, the chance that I will find a strong correlation is slim; in addition, the variation between data points is so small relative to the precision of the data. I do expect to find a trend though, once I refine the method. And if there are outliers, I will personally go to the points of interest, look around, and ask myself, “What is different about this spot?” and wait until a burst of inspiration blows my way.

If it makes it past these tall buildings.


June 22, 2013

“Still I say, there’s a way for us”

Professor Edward Ng had a smile on his face as he invited us to sit. His assistants poured us tea as he gestured to the dim sum on the lazy susan. Around the lunch table sat the architects, civil engineers, urban planners, and IT specialists that comprise his research team. After getting our names, one by one he introduced each of his team members and explained their research focuses, making light-hearted jokes about them along the way. After asking us a few questions about our background and interests, he turned back to his team, and the tone shifted. He went around the table again — this time, asking each researcher to report on progress. Some he acknowledged, and those that fell short of expectations he questioned further. Quickly we could see what it is he wanted: not just effort, not just hours, but results.


Carter in front of the Victoria Harbour.

The next day he explained the background of our research questions, his hope to be able to make quick predictions when adding buildings, to be able to calculate wind speed at a single point based on the shape and structure of the city. The wind engineers, he explained, said it could not be done; he assured me, however, that he would not give up. Deliverables? By the end of the summer I am to have a research paper for him. “Okay, if there are no more questions, that’s it. If you have a question, don’t ask me, I don’t know the answer either. You’re on your own now.”

Indeed, since then I have independently written an in-depth literature review to understand what others have since tried, and brainstormed some ideas for predictive methods. Occasionally I discuss my questions and ideas with Yuan Chao, a fellow researcher soon to receive his Ph.D. for his studies in similar topics of wind.

As of today, I have read books about wind, building aerodynamics, and urban climates, as well as numerous papers on the topic of wind. I feel my understanding of wind is sufficient to move forward. I have numerous ideas for how to predict wind speed, many of which can be tested with data we have already collected. My feeling is the same as the professor’s: the impossible may indeed be plenty possible.

Now, it’s time to prove it.

June 7, 2013

Hong Kong: Welcome to the Urban Heat Island

“Hi, I’m Austin.”

“I’m Carter! I guess we’re roommates!”

“Nice meeting you! Did you just get back from a run?”

I turned and looked into the mirror to my left. I sure looked like it. In fact, I had just walked casually back to my hostel from the train station, but my first few days in Hong Kong ingrained in my head a key concept that would be the basis of my research this summer:

Indeed, it is too hot here.


Tolo Harbour, or Tai Po Hoi, a sheltered harbour in northeast New Territories of Hong Kong.

Today was a stark contrast — the sun was still bright and sky was clear, but a light breeze blew across my face as I climbed the hill back to my hostel. It was a poetic conclusion to my first week researching the urban heat island effect; I had spent the bulk of the time studying papers on wind availability in high-density cities, including the effect of wind speed on pedestrian comfort. I stopped and looked across the beautiful Tolo Harbour. The metropolitan areas of Hong Kong would not feel this breeze, not with the tightly-packed skyscrapers creating giant wind walls, keeping the fresh ocean air out and the hot, polluted urban air in.

The research question that the professor has commissioned me to explore is the following: is there an urban morphological way to predict the near-ground wind velocity ratio for a high density city? There is no definite answer available, but with a thick book of accurate wind tunnel data and numerous relevant research papers, including many written by the distinguished Professor Ng himself, the task is daunting but inviting.

With Professor Ng in Germany, I’ve had the unique opportunity of seeing the system he has implemented before meeting the man himself. Stationed at the top of the architecture building, Professor Ng’s task force has researchers working on different sections of the urban climate puzzle – some study solar radiation, others wind availability, yet others green design. Meanwhile, in another section of the same office, members of the charity he founded to build sustainable bridges in poverty-stricken areas of China meet regularly. I met briefly with a graduate researcher also exploring wind availability who answered a few questions, pointed me to relevant literature, challenged me to find creative solutions, and left me to my own business. It was clear then that I would be expected to conduct true, original, self-motivated research; this would not be a summer of data entry and coffee runs.

It’s too hot for coffee anyway.

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