Hello, I want to modify the proportion of cities in the surface data, but there is no matching data, only "percent urban for each density type" is found. However, the attribute of this data is PCT_URBAN(numurbl=3, lsmlat=192, lsmlon=288). I don't know what numurbl1, 2 and 3 mean respectively, and if I want to modify it, how should I modify it? Looking forward to your reply
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Proportion of cities in surface data
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PCT_URBAN is the percent of each urban density type. The density types in order are tall building district (TBD), high density (HD), and medium density (MD). If you change those percentages, e.g, increase them, then you'll need to decrease some other surface type (e.g., PCT_NATVEG, PCT_CROP, PCT_LAKE, etc.). The sum of PCT_URBAN, PCT_NATVEG, PCT_CROP, PCT_LAKE, PCT_GLACIER, PCT_WETLAND needs to be 100%.
Thank you, oleson. Can I modify it directly on the raw surface data or do I need to use some tool to make sure that the model runs correctly?PCT_URBAN is the percent of each urban density type. The density types in order are tall building district (TBD), high density (HD), and medium density (MD). If you change those percentages, e.g, increase them, then you'll need to decrease some other surface type (e.g., PCT_NATVEG, PCT_CROP, PCT_LAKE, etc.). The sum of PCT_URBAN, PCT_NATVEG, PCT_CROP, PCT_LAKE, PCT_GLACIER, PCT_WETLAND needs to be 100%.
Thank you, oleson. Let me have a tryYou could modify it directly in the surface dataset.
Hello, oleson, would you please tell me if there are any other attributes reflecting urban proportion changes besides PCT_URBAN? In other words, can I change the city ratio only by changing the PCT_URBAN attribute? Is there any other way?You could modify it directly in the surface dataset.
好的，谢谢你这是最合理的方法。
oleson, I have two more questions.PCT_URBAN is the percent of each urban density type. The density types in order are tall building district (TBD), high density (HD), and medium density (MD). If you change those percentages, e.g, increase them, then you'll need to decrease some other surface type (e.g., PCT_NATVEG, PCT_CROP, PCT_LAKE, etc.). The sum of PCT_URBAN, PCT_NATVEG, PCT_CROP, PCT_LAKE, PCT_GLACIER, PCT_WETLAND needs to be 100%.
1. What is the standard for dividing tall building district (TBD), high density (HD), and medium density (MD)?
2. What data should I refer to if I want to modify this attribute?
Looking forward to your reply.
This paper describes how the urban data was derived:
Jackson, T.L., J.J. Feddema, K.W. Oleson, G.B. Bonan, and J.T. Bauer, 2010: Parameterization of urban characteristics for global climate modeling, A. Assoc. Am. Geog., 100:4, 848-865, DOI:10.1080/00045608.2010.497328.
Jackson, T.L., J.J. Feddema, K.W. Oleson, G.B. Bonan, and J.T. Bauer, 2010: Parameterization of urban characteristics for global climate modeling, A. Assoc. Am. Geog., 100:4, 848-865, DOI:10.1080/00045608.2010.497328.
Thank you very much, olesonThis paper describes how the urban data was derived:
Jackson, T.L., J.J. Feddema, K.W. Oleson, G.B. Bonan, and J.T. Bauer, 2010: Parameterization of urban characteristics for global climate modeling, A. Assoc. Am. Geog., 100:4, 848-865, DOI:10.1080/00045608.2010.497328.
Hello, oleson. I set up an experiment based on your suggestion to expand the proportion of cities within a certain area. But what puzzles me is that when PCT_URBAN becomes larger, how will the roofs, roads and walls in the city change? How do I check these changes? And how do you check the area of each of these three attributes? Only their respective albedo data are included in the input data. These two questions have been bothering me for a long time, and I am looking forward to your answers and help.PCT_URBAN is the percent of each urban density type. The density types in order are tall building district (TBD), high density (HD), and medium density (MD). If you change those percentages, e.g, increase them, then you'll need to decrease some other surface type (e.g., PCT_NATVEG, PCT_CROP, PCT_LAKE, etc.). The sum of PCT_URBAN, PCT_NATVEG, PCT_CROP, PCT_LAKE, PCT_GLACIER, PCT_WETLAND needs to be 100%.
Currently, the morphological properties don't change when PCT_URBAN changes. So, properties such as building height to street width ratio (CANYON_HWR), roof fraction (WTLUNIT_ROOF), pervious fraction of the canyon floor (WTROAD_PERV), building height (HT_ROOF) don't change. You can probably figure out how the areas of the individual surfaces change by making use of these properties. E.g., if the urban area changes from 1000 m2 to 2000 m2 and the roof fraction is 0.5, then the roof area increases from 500 m2 to 1000 m2.
oleson, thank you so much for answering my questionCurrently, the morphological properties don't change when PCT_URBAN changes. So, properties such as building height to street width ratio (CANYON_HWR), roof fraction (WTLUNIT_ROOF), pervious fraction of the canyon floor (WTROAD_PERV), building height (HT_ROOF) don't change. You can probably figure out how the areas of the individual surfaces change by making use of these properties. E.g., if the urban area changes from 1000 m2 to 2000 m2 and the roof fraction is 0.5, then the roof area increases from 500 m2 to 1000 m2.
Hello oleson， WTLUNIT_ROOF（numurbl=3， lsmlat=96， lsmlon=144）目前，形态特性不会随着PCT_URBAN的变化而改变。因此，建筑物高度与街道宽度之比 （CANYON_HWR）、屋顶分数 （WTLUNIT_ROOF）、峡谷底部透水部分 （WTROAD_PERV）、建筑高度 （HT_ROOF） 等属性不会改变。通过使用这些属性，您可能可以弄清楚各个曲面的区域是如何变化的。例如，如果市区从 1000 m2 变为 2000 m2，屋顶分数为 0.5，则屋顶面积从 500 m2 增加到 1000 m2。
numurbl=0、1 和 2 是否分别对应于 TBD、HD 和 MD？如果我想知道每个网格点中屋顶面积的比例，我是否需要计算 WTLUNIT_ROOF*PCT_URBAN还是属性WTLUNIT_ROOF已经直接表示了这一点？非常期待您的回复，谢谢！
Hello oleson, WTLUNIT_ROOF (numurbl=3, lsmlat=96, lsmlon=144)Currently, the morphological properties don't change when PCT_URBAN changes. So, properties such as building height to street width ratio (CANYON_HWR), roof fraction (WTLUNIT_ROOF), pervious fraction of the canyon floor (WTROAD_PERV), building height (HT_ROOF) don't change. You can probably figure out how the areas of the individual surfaces change by making use of these properties. E.g., if the urban area changes from 1000 m2 to 2000 m2 and the roof fraction is 0.5, then the roof area increases from 500 m2 to 1000 m2.
Do numurbl=0, 1, and 2 correspond to TBD, HD, and MD, respectively? If I want to know the proportion of the roof area in each grid point, do I need to calculate WTLUNIT_ROOF*PCT_URBAN or does the attribute WTLUNIT_ROOF already directly represent this? Look forward to your reply very much, thank you!
Thank you very much oleson for your answer and for the information you shared earlier. I also read some of your articles on city models recently, which made me learn a lot. It gave me some insight into the city model, but it was relatively shallow. I hope I can continue to get your answers and help in the future.Yes to your first question.
WTLUNIT_ROOF represents the fraction of roof in the urban area. If you want the fraction of the grid cell that contains roof, then WTLUNIT_ROOF * PCT_URBAN.
At the same time, I want to continue this question, I want to know the proportion of roof area in each grid point, do I need to add up the three layers of data? For example, the value of WTLUNIT_ROOF0 * PCT_URBAN0+WTLUNIT_ROOF1 * PCT_URBAN1+WTLUNIT_ROOF2 * PCT_URBAN2 represents the actual roof area ratio of the grid, or can a certain layer of data be represented? Or are they not simply additive relationships?
Thank you oleson for your answer. I have a new question. I only found the surface data of 2000 on the website (surfdata_1.9x2.5_78pfts_CMIP6_simyr2000_c170824.nc). Is there any new surface input data? For example, after the year 2000? Because the surface situation has changed greatly in recent years, if not, I would like to compare the new surface data applied to the input of cesm, how should it be made?Yes, you can add them up as you've indicated.
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