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Hi. I have three questions about Landsat 8 and LST.
Q1.
I want to use Landsat 8 TIRS data to calculate Land Surface Temperature (LST) of the arctic regions.
So far, I have pre-processed BT and TOA from Level 1 DN, converted to LSE, and added NDVI to obtain the LST value.
However, I have some anxiety that this method is inaccurate than using Level 2.
Nevertheless, the reason why I could not use Level 2 ST (Band 10) product is because of the data gap due to missing of ASTER GED data (figure).
As you can see from the link below, the high latitude regions such as Greenland and Iceland have data gap issue in ST products.
I wonder if there are some methods or alternative to overcome the data gap.
Q2.
I know that Sobrino 2004's method is frequently cited in LST calculations, and I know that there was a stray light problem with Landsat 8 TIRS.
However, recently I got to know that there are so many algorithms for converting TIRS images to LST (e.g., Split-Window or Single Channel)
Also, I found out that the stray light issue has already been calibrated in 2019.
Now, I wonder which algorithm is most appropriate for converting Landsat 8 TIRS images to LST.
Q3.
Is there no need to preprocess Level 2 SR products for NDVI or other band combinations?
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If Landsat 8/9 Level-2 products express your AOI properly, use Level-2. They reduce preprocessing time so that you can spend more time on analysis and writing.
However, if the quality is not enough for your AOI, Level-1 may be the only choice. It is essential to choose the appropriate LST retrieval algorithm for your AOI's situation (e.g. land cover). I spent a lot of time selecting them.
Or, if your AOI is very wide, you can use alternatives such as Sentinel-3 data.
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Hello everyone, I picked some pieces of questionable small shelly fossils from Greenland but am still in trouble recognizing them. I was wondering whether it is a fragment or a whole fossil itself. You can see the distinctive lattice-like structures throughout the specimen. Any kind of idea is welcome.
- Age: Cambrian Series 2, Stage 4
- Occurrence: Greenland
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Hi, please refer to Kouchinsky et al., 2022, Early–middle Cambrian stratigraphy
and faunas from northern Siberia. Acta Palaeontologica Polonica 67 (2): 341–464. In their Fig. 20 you will find the same fossil.
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Valentin Amrhein, Sander Greenland, Blake McShane and more than 800 signatories call for an end to hyped claims and the dismissal of possibly crucial effects of statistical significance:
The biggest argument: “Statistically significant” or “not statistically significant” is too often easily misinterpreted to mean either “the study worked” or “the study did not work.” A “true” effect can sometimes yield a p-value of greater than .05. And we know from recent years that science is rife with false-positive studies that achieved values of less than .05:
There are a number published articles which substantiate above-mentioned views. It has been my personal experience that because of poor and erratic performance of check varieties across replications, LSD gets enhanced and we loose some promising candidate genotypes for ever. It is debatable whether the time has come to totally abandon the concept of statistiscal significance from biological or social science experiments. Dear RG members, you are most welcome to express your opinion.
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Dear Dr. Arbind K. Choudhary , I do not think so.
I agree with the information provided by you while initiating this discussion, the statistical significance (what or how much is acceptable range? - is debatable) and its relevance need further investigation.
I completely agree with Dr. Anamitra Roy , the pandemic has compelled us do continue our research work without much of statistical tools.
It should be noted that the statistical test are one of the ingenious methods of extracting the hidden truth (pattern). It saves us time, effort and money.
Warm regards
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  1. During the daytime, shortwave net radiation is greater than 0 due to albedo is less than 1. If all-wave net radiation shows negtive value for Arctic, Greenland, and Antarctic area, it indicates surface energy is being lost throughout the daytime and night. Is this correct? If so, how to explain it?
  2. Anyone konw this issue, thanks a lot for your reply.
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Dear Jiang,
I am also facing the same issue with data. How you sort out?
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We are working on a revised version of the global water cycle and need estimates of surface and deep ocean water. We have found several estimates from popular sources (websites and magazines) ranging from 80-90% deep water, but haven't found peer-reviewed estimates. The line between surface and deep water is often set at a neutral density of 28.11 kg/m3 (e.g. Ganachaud and Wunsch 2000, Nature). We are also looking for global estimates of ice discharge (mainly Greenland and Antarctica) if you have any good references. Thanks!
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for Ice sheets melting, look at: Gardner et al., 2013. A Reconciled Estimate of Glacier Contributions to Sea Level Rise: 2003 to 2009. Science 340, 852
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why the maximum age varies in the ice sheets those are present in the earth. (Between Antarctica and Greenland)
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It's useful to clearly note the distinction between the age of the ICE and the age of the ICE SHEETS. The age of the oldest cored ice is about 125 and 800 kyr, respectively for Greenland and Antarctica, and there may not be much older ice, because of the slow lateral movement of the ice sheets towards the sea.
The age of the ice sheets as entities is much older, probably going back to the Oligocene for Antarctica and Pleistocene for Greenland (with or without periods of full deglaciation).
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I'm looking for examples of Community-based economic developement project in the Arctic. I know well the Canadian context but I'm looking for examples in Alaska, Greenland, Russia and in the Nordic Countries.
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The following might get you started:
BurnSilver, S., Magdanz, J., Stotts, R., Berman, M., & Kofinas, G. (2016). Are mixed economies persistent or transitional? Evidence using social networks from Arctic Alaska. American Anthropologist, 118(1), 121-129.
Colt, S., Berry, K., Bayham, J., Meyer, S. R., Fenichel, E. P., Finnoff, D. C., ... & Meiners, D. (2017). The Alaska Village Energy Model. Environmental Resource Economics.
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The potential energy of the ice caps as an additional energy source for accelerate the deglaciation and global warming
In modern climatology general scheme of the global hydrological cycle and energy budget of the Earth have several disadvantages that exist for over a hundred years. But, sooner or later, they must be corrected. Now is the time to do it. What the mistakes we talking about? This is because the above schemes did not include the huge potential energy accumulated in the glaciers. The energy accumulation accompanied by accumulation of ice. That lasted thousands of years. Since the beginning of deglaciation the ice turns to water which escapes from a certain height. As a result, the potential energy of the ice turns into kinetic energy of water. The total potential energy on the start the melting of glaciers is determined by average height of the glacier, the total weight of ice and gravity. That is general equation of Newton physics - mgh.
How much energy had been realized since the melting of glaciers? It is easy to calculate. Over twenty thousand years have passed since the beginning of quick glacial melting, simultaneously the sea levels rose to 120 meters. Thus, this value is multiplied by the area of the water surface of the Earth and on the average glaciers height (about 2000 meters). Taking into account the gravity we find the total energy released from glaciers over last twenty thousand years. Perhaps, it will be many.
Today the annual volume of energy released from glaciers can be calculated only for Greenland. From research we know that every year about 200 cubic kilometers of water from the glacier goes into the Ocean. This amount is about 70 percent water coming from all modern glaciers, together with Antarctica ice cap.
Multiplying all values we find quantitative amount of the annual release of energy. It is 4 000 000 000 000 000 000 Joules. or 1,111,111,111 MWh. If we take for comparison most powerful hydroelectric in the world Three Gorges Dam (China) - 22, 5 MW then this energy it will produce over 49,382,716 hours, or 2,057,613 days. It ultimately equals 5637 years. All together of the world hydroelectric energy produces such energy somewhere for a thousand years.
Despite the fact that in compare with total energy budget of the Earth these values, at first glance, are miserable. But here we must remember that this energy is working on a very limited area of melting glacier. Today it is about 50 000 km2 for Greenland. And all the energy goes to further the melting glacier. That is, it operates in the most vulnerable areas.
Research the melting of Greenland glaciers shows that within the general area of melting the water initially collected in the supraglacial lakes and then quickly falls down through the channels in the body of ice. These inlet channels called moulin. Their area against the background of the ice surface, probably are less than 1%. In reality, the space concentration of energy is many more.
That's why this energy requires consideration when studying other territories and the causes of global warming. Confronting of it is not possible, but the accounting of this energy permits make more accurate predictions of events for the future.
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Dr. Henrik and Mr. Wasyl,
Very good discussions on glacier and energy. We are learning. Thanks and regards
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In recent years we have been observing various pro-independence movements around the world such as Catalonia, Scotland, Bougainville, New Caledonia, French Polynesia, Greenland, Papua, California, Guam, Faroe Islands, Azores, Kurdistan, Cook Islands, Niue, Tokelau and Rapa Nui. Are we experiencing a new wave of nationalism and independence, like that of the 1960s and 1990s?
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This is probably too narrow for your interests
you might google work by Tom nairn very good
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There are many questions about China's involvement in mineral resources in Greenland I'd like to ask. For example, what kind of minerals are China exploring? What're the scales? How does the exploration affect local communities environmentally and/or economically? How do Chinese investors interact with local governments and citizens in Greenland? I look forward to hearing your findings on these questions.
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Thanks a lot for all the helpful responses! My work so far focuses on the socioeconomic and political impacts of mining industries in China. But I'm interested in comparing the strategies and consequences of China's domestic vs overseas mineral exploration. I look forward to reading all the references mentioned above.
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Yes. Observations show a global-scale decline of snow and ice over many years, especially since 1980 and increasing during the past decade, despite growth in some places and little change in others. Most mountain glaciers are getting smaller. Snow cover is retreating earlier in the spring. Sea ice in the Arctic is shrinking in all seasons, most dramatically in summer. Reductions are reported in permafrost, seasonally frozen ground and river and lake ice. Important coastal regions of the ice sheets on Greenland and West Antarctica, and the glaciers of the Antarctic Peninsula, are thinning and contributing to sea level rise. The total contribution of glacier, ice cap and ice sheet melt to sea level rise is estimated as 1.2 ± 0.4 mm/yr for the period 1993 to 2003.
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Yes. Observations show a global-scale decline of snow and ice over many years, especially since 1980 and increasing during the past decade, despite growth in some places and little change in others
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The picture of this brittlestar is from the North West Atlantic at about 900 m. depth. The location is near the Greenlandic coast.
Can this Brittlestar be confirmed as an Ophiomusium lymani ? or could I be looking at something completely different
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Thank you for all your answers. I have something to work with now :-)
Helle
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I am using Modis visible subsets and swath images with 250 m and 500 m resolution to visually characterize the occurrence of sea ice leads for specific regions in the Arctic.
Unfortunately the Images prior to 8 May 2012 are not available at the NASA websites anymore due to a hard disc failure and no solution of the problem is expected for the near future. Therefore I am looking for satellite imagery that is highly enough resolved to distinguish single sea ice leads.
My study period is March to April 2012. The regions are in the western Arctic north of Svalbard, Greenland, Ellesmere Island and in the Beaufort Sea.
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Hi Lukas, please check, whether the data presented at
might be an option for you and let me know in case you are interested. There will be an update for the missing years soon.
Best wishes,
Sascha