I was wondering what an annual air temperature value is and how it would would be determined. And the question suggests you are interested in permafrost melting, perhaps for CO2 release, or something else. I was thinking that the aspect, slope, cover factor (eg snow, vegetation, bare soil) all would be important to how much ambient solar energy is exposed to the site, and also how much of it can be absorbed as energy to melt permafrost. You may have substantial periods of deep freezing, and the temperature variances and solar exposure makes no difference. What to identify would be days where the temperature, solar radiation and ground conditions can effectively penetrate and melt permafrost. Some aspects and slopes, land cover would be different rates than others. If you are trying to quantify the effects of climate change, often this is takes years of data. If you have stream gauging stations in your area, the periods when the streams are iced up are obviously not periods of permafrost melt. Periods when then soil is exposed and plants start to grow suggest permafrost has had the chance to melt some. This plant growth beginning and permafrost melting may be after the peak stream flows. It would probably take some research to help define when the permafrost melt begins. I don’t think temperature by itself would be the only factor to consider, but at least try to identify the periods of effective temperature, solar radiation, land exposure and cover and correlate those to the site. There was an inexpensive tool that we used sometimes years back called the solar pathfinder I think. You can take it to the site and determine from the inserts the solar angles for varying times of the year, and could address some slope and aspect differences in solar radiation for the site. It was somewhat helpful in learning what streamside vegetation is needed to offer shade to help limit solar changes when harvesting trees to maintain fishery habitat for temperature and available woody debris inputs.

You are not the only one who doubts the existence of global warming. I noticed this after 1998, when there was a short but very statistically significant increase in temperature. It was not caused by the greenhouse effect. Look at charts from the internet.

What matters about your statistical output is the quality of your dataset. Similarly, Whenever the term climate change come into your mind, you need to notice that the change in temperature might be (+)warming or (-) cooling. Statistically speaking, it might be significant or not. You need to accept the result and compare it with similar works in proxy areas.

William F. Hansen thanks for your advices, i will check for changes in vegetation due to runoff from permafrost's active layer. The area i think that may be similar to White Mountains in California, there is not much vegetation, but "vegas" are formed in some parts of the former glacial valleys.

It's one of the goals of the project to evaluate incoming solar radiation, and outgoing infrarred aswell (both challenging because of lacking atmospheric information), or at least surface temperature. Aspect is key here, in the main valley the estern side has predominantly north facing surfaces and in consequence the periglacial landscape is less developed than in the western side, that has rock glaciers and protalus lobes. There is also a lot of "shading", because of high steep walls of ancient "cirques".

I was looking for trends to extrapolate air temperatures to a future time and in this way "model" the spatial distribution of the landforms (rock glaciers). In a certain way, from what i learned about heat transfer mechanisms air temperature have a certain role in the initiation of convection processes. Also crack water freezing contributes to fragmentation and production of blocks on the surface of the glaciers (this is the atribute that keeps them cool because of the bad thermal conductivity of air)

@Borys Kapochkin I was trying to find linear trends on those datasets and i didn't find any, judging from the mean annual values. One have to keep in mind that the data is kind of "synthetic", there are lots of variables derived from anothers and not meassured directly, or coming from interpolation of very far data. I opened this question hoping to receive suggestions on other ways to meassure the trends, needless to say any kind of feedback is welcome.

@Addisu Damtew Atnafe Yes, it will be useful to have more stations to compare results from data sets and real data,

Matias Lestussi

Air temperature, which you are using, is determined by absorption of infrared radiation from the surface by greenhouse gases, mainly water vapour and carbon dioxide. In a region where there is snow, ice and permafrost the surface temperature will remain around 0C and so the air temperature will also not increase by much. Moreover, although CO2 is increasing, water vapour will remain insignificant while the surface temperature remains at freezing temperature.

This means that any trend you measure at present will be greatly exceeded when the ice has gone. In the arctic temperatures are rising nearly four times faster than the rest of the world. See:

Rantanen, Mika, Alexey Yu Karpechko, Antti Lipponen, Kalle Nordling, Otto Hyvärinen, Kimmo Ruosteenoja, Timo Vihma, and Ari Laaksonen. ‘The Arctic Has Warmed Nearly Four Times Faster than the Globe since 1979’. Communications Earth & Environment 3, no. 1 (11 August 2022): 1–10. https://doi.org/10.1038/s43247-022-00498-3.

But the Arctic north of 80 N never gets above 2C (275K) http://ocean.dmi.dk/arctic/meant80n.uk.php

(because of the sea ice?)

Everyone knows about the ambiguity of the initial data in the trend of air temperature changes. Many are also aware of the ambiguity of the initial data in the trend of changes in ocean level. I support the destruction of hydrocarbon energy, which creates a greenhouse effect and makes the ocean acidic. Show us the "correct" data and we will analyze this data.

Thanks Alastair Bain McDonald and Borys Kapochkin for your answers, i will keep in mind the decrease of water vapor on a 'snowy' scheme, and it's long term effect on air temperature. Maybe that is the reason, actually, why i'm not seeing trends in the data. I'm in the middle of the way trying to graph ERA5 model data to look for trends, maybe i'll add what comes off from that to the question (i'm not sure if this is a correct way to express it). I will also evaluate water vapor values in time, maybe i can add the data to the question too.

Hi Matias Lestussi ,

What I was trying to say is that the greenhouse effect depends on the surface temperature. It you have an ice covered surface, its temperature will not rise until the ice has melted. This probaly also applies to permafrost and snow. It is the surface which produces the black body radiation that is absorbed by the greenhouse gases. So I am arguing that is the reason you do not see an increase in temperature, but I am not sure I can prove it as there are other factors at work like specific humidity and advected air.

Thanks Alastair Bain McDonald I understand. The surface of the study area isn't covered by snow all year, the climate is semi-arid, and permafrost is discontinuous. It is a high altitude (~4500 m. asl) mountainous region. My intention is to focus on surface temperature and atmospheric humidity variation from now on, also on the infrared radiation emited by the surface on the area, and incoming solar radiation. There's still a lot of work to do