Burgastyn Els, Mongolia’s highest desert (2/3)

Journey photo album

Every year new ice sculptures appear on the Chinggis Square, Ulaanbaatar

We are here but the flight is delayed to the next day because of snowstorm in Zavkhan aimag

On the way to Erdenekhairkhan (85 km of emptiness)

Maybe this will be my home for the next two weeks

Halo, a very common optical phenomenon in the mongolian winters

Some of my roommates. I think all of us like the cold

Near Mukhart river source in the next morning (30 km snow covered track). This will be the starting point of all my trips to the research area

Pretty chilly, it was -25 degrees in Erdenekhairkhan, which is not a particularly cold place as it lies on a plateau in slope. The next night can be promising

At sunrise, approaching the natural amphitheatrum of Mukhart

I know this scenic place from two years before. One quarter of the way is done

Okay, so that’s my direction. Burgastyn Els desert in front of me

Despite the isolation, the dunes are covered with many animal trails

Looking back, more than half part is done. Pretty tiring terrain for a heavy backpack and big snowboots

But most of the trails are made by these…

…and these guys. Horses and yaks are left to graze on the dunes unsupervised

In the afternoon I reached the planned camping spot on the southern col of the chosen basin

First view of the unnamed sandy depression

Arriving at the bottom. Looks good, the weather also

At 5 PM the mini weather station started its activity: -28 degrees now

Soon after the sun disappeared the temperature was falling fast

-33.5 degrees at 17:40, still sunshine on the ridges

Time to go back to the tent (1 km in straight line)

Only a thin layer of snow here, the wind cleared the exposed parts. On the bottom is 20-25 cm, but some areas have even above 50 cm

Dinner time: dried fruits, one of the best and simplest solution for extreme cold

The first part of the night was completely clear and calm, later cirrostratus clouds were invading the sky. Near surface measurement at my camp (dawn). In the basin must be much colder

That’s right, went well below -40. Still no wind, but because of the thicker cirrostratus the morning temperature was only -35 degrees

The surface was two degrees colder, very common on the negative topography (convex and inclined terrains can have much more differences)

After 10 AM I started the way back. The tent will remain here, I trust the calm of the anticyclone

These are the most tiring parts: steep, snow covered sand. Beside the legs it needs also significant upper body strength

Some parts are completely full with horse and yak trails

Mukhart’s outer (convex) contour is closer and closer

This view is always welcomed. Now also means that the most difficult part is over

First and last guy seen during the two day trip. He came on horseback to the base of Mukhart, than climbed the abrupt part on foot

I can see the car. Actually I saw it first from the rim of the amphitheatrum

Good to see that the driver is very conscious, coming here much sooner to wait me with warm food

Playing cards is the main program in a yurt. Unfortunately usually accompanied by smoking…

Magpie is the most common bird here in the winter

And I can’t miss out this: Erdenekhairkhan’s weather station

Yurt change the next day: too many children (including an infant) made the essential rest impossible. Sorry guys…

Domestic goats on the hill near the village. Much smaller and with thicker coats than european ones

Yeah, that’s a vulture. Only 100 meters from the settlement

Altan Khairkhan (Golden Holy Mountain), a proeminent landmark

Back to the cards. And smoke. Okay, it’s not that bad

Climbing a rocky peak a few km from the settlement. Ibexes are living here…

Much cloudier today, but the following night looks promising

Yaks again, more exemplars this time. The snow partially disappeared from the exposed slopes. Beside the sun and the wind, the animals are also contributing to this, eating it in place of water

The backpack is less heavy and I can follow my tracks from the previous trip. Feeling stronger I climbed the rocky peak instead of circumventing it. Worth it

A snow shower started, but it was short and weak

I found my tent moved from its original place. The south-eastern wind carried it inside the neighboring hollow. Maybe a better place to spend the next night, if it’s windy

Goji berries, pecan nuts and a local meal “aaruul” (kind of dried yoghurt) is the menu today. Let’s check the tripod with the thermometer

-38.5 degrees for the missing period (13-17 January)

Observing on GoogleEarth, I was curious to see what kind of vegetation is on the slope of the nearby mountain. As I later understood from the locals, this is exactly the “burgas” (bush), which gave the desert’s name

I also made a walk to the northern col (another 1 km in straight line) to measure its elevation (center of image). It was almost the same as GoogleEarth showed: 2221 m. That means the tripod is 27 meters deep inside the basin

This hollow is the actual bottom of the basin (2192 m), but I left the tripod in the original place because of the better sky view factor

Warmer than the first time: -21 degrees in the afternoon

Back to the camp. I’ve moved the tent only a few meters from the place the wind was carrying it. Here is more protected, relatively flat and still not on the hollows bottom

The evening and the first part of the night was fine (clear and calm), but after midnight the wind started to intensify and till the morning completely destroyed the inversion of the basin. Minimum of the night: -40.9 degrees Celsius

Because of the wind I was constrained to pack the tent (it wasn’t able to stay in place even in the hollow). On the way back I met the horses again

The driver was there well before my arrival, this time with the second yurt’s owner

Lunch at the mayor’s house the next day. They heard about my activities and invited me

This time I was lucky and saw the ibexes on the rocky slopes (younger ones)

The last research trip started with some difficulty because of the snowdrifts. But we were three and solved the problem soon

Warmer today, very low temperatures are unlikely for the following night

The amphitheatrum have some visitors this morning

I had the strategic advantage observing them from the rim, therefore plenty of time to make pictures

Partially cirrus covered sky today. This setting will continue also in the night

Now it’s calm, I will leave the tent on the ridge again

-39.6 degrees is the minimum for the missing period (18-22 January) and only -16.5 now

I’ve climbed to the highest peak of the western ridge (around 2390 meters) to see Ulaagchiin Khar lake on the other side

The researched basin from the ridge. You can observe the “burgas” vegetation on the mountains slope

-26.3 degrees at dusk. Not very cold, but the decrease was significant (10 degrees in less than two hours). I didn’t slept much this night. Beside that I’ve often checked the sky, wolfs were howling an entire hour in the latter part

And here is the main event of the night and maybe of the entire research: the small hollow beside my tent had -37 degrees (at head level) in the early morning and -39 degrees near the snow surface. That’s a solid 20 degrees lower than the temperature at my camp (only 50 meters away!) where it was -17 degrees. Even weirder is that there was colder in the early evening (-19 degrees), despite the clear and calm conditions during the entire night

The main basin reached -36.8 degrees. That means the small one was the same, actually even slightly colder (!)

This was a characteristic night with generally constant temperature drop. The instant morning temperature was close to the minimum (around -36 degrees)

Sixth and last time on the same track, became familiar until now

The more exposed parts of the dunes lost the snow cover during the last days

An entire labyrinth of trails in this area

Mukhart for the last time. Remember how white was in the first day?

This wild cereal is very common on the dunes

…and to Donoi airport in the next morning

Otgontenger (4008 meters), the highest peak in the Khangai mountains and one of the most sacred in Mongolia

To be continued…

Burgastyn Els, Mongolia’s highest desert (3/3)

Evaluating the measured values

First research night (12-13 January)

The tripod with the minimum thermometer was set around 5 PM at the bottom of the basin. The sky was clear, no air movement, still sunshine at that time. The alcohol column of the instrument showed -28 degrees Celsius. Shortly after the installation became shadowed and until 17:40 (when I left the hollow) the temperature decreased to -33.5 degrees. Near the snow surface I measured -36 degrees.

The first part of the night was completely clear and calm at my tent. After 3 AM (it was almost full moon) I observed some cirrus, than cirrostratus clouds invading the sky. At dawn I measured -17 degrees at head level and -23 close to the surface near my tent. In the hollow was -35 degrees in the early morning (-37 close to the surface), while the minimum of the night reached -41.9 degrees Celsius. This will remain the lowest temperature captured in the entire research period. In the same night Tsetsen Uul (the most representative weather station of the area) reached -38.4 degrees.

The lowest temperature of this research: -41.9 degrees Celsius

The 13-17 January interval

I left the research area in the morning of 13th January. As I had no logger to record the temperature curve, the single certain data what I will have after my return is the minimum value for the entire missing period. I visited the hollow for the second time in the afternoon of 17th January, when I found the index of the instrument stopped at -38.5 degrees Celsius. I can’t be sure which night gave this value, can’t even exclude the same morning when I left the basin. However most likely happened on the night from 14 to 15 January, when Tsetsen Uul reached -37.2 degrees.

Second research night (17-18 January)

The afternoon was changing from full sunshine to partly cloudy (cirrus-cirrostratus with some altocumulus lenticularis) and was warmer than on 12th, with the temperature around -21 degrees. The evening started well with clear sky and still air, but later in the night it became windy. No clouds till the morning, but the intensified wind completely destroyed the inversion of the basin. The temperature raised from the -40.9 minimum value to above -20 degrees before the sunrise. The same pattern can be observed in the statistics of Tsetsen Uul, which recorded -36 somewhere in the early night hours and warmed up to -19 degrees till the morning.

The 18-22 January interval

I left the research area in the morning of 18th and visited the hollow again in the afternoon of 22th January, when I found the thermometer’s index stopped at -39.6 degrees Celsius. This almost certainly happened in the morning of 19th January, when Tsetsen Uul recorded -35.6 degrees.

Third (last) research night (22-23 January)

The entire day was generally fine, also much warmer, with the afternoon temperature of -16 degrees. There were only intermittent light air movements, but thinner cirrus and cirrostratus clouds were partially covering the sky constantly. This setting continued also in the night, when the sky was starry, but slightly blurred. No wind till the morning. I’ve measured -17 degrees near my tent at dawn, which was a surprisingly high value, as I saw 2 degrees colder in the early evening hours in the same place (!) In the basin the minimum thermometer’s index was stopped at -36.8 degrees, while the temperature at the moment was also close to this value (around -36 degrees). This was a good night, very likely presented the characteristic temperature curve, but because of the too high starting temperature couldn’t reach too low, despite the 20 degrees of decrease.

But the most impressive happening was when I descended in a hollow between the dunes, just beside my tent. Certainly no more than 10 meters deep and with the drainage area not bigger than a soccer field. To my great surprise at the bottom of this banal concavity the head level temperature was -37 degrees Celsius at 8 AM (already -35 in the earlier part of the night), a full 20 degrees lower than on the nearby ridge and even slightly colder than the minimum for the entire night in the big basin with hundreds of times more drainage area! Meanwhile the near surface temperature was -39 degrees.

General conclusions

Compared with Tsetsen Uul the Burgastyn Els station reached lower minimums in all the 5 described intervals. The smallest difference is 1.1 degrees, the biggest 4.9 degrees, the average 3.0 degrees Celsius. In three of the five cases the difference was bigger than 3 degrees. According to the statistics on Ogimet Tsetsen Uul had only 8 cm of snow cover that time, while the researched basin had around 20 cm. In my opinion this could give an advantage of 1-2 degrees, but not above 3 degrees.

It can be noticed that the three bigger differences coincide with the three coldest measurements in the frost hollow, while the remaining two with less impressive discrepancies are the ones, when the cold was less severe. Tsetsen Uul’s lowest reading was also on 13th January, but was 3.5 degrees milder than in the high desert.

The minimum temperatures of 13th January in Central Asia (source: Ogimet). None of the stations presented on the map reached lower than my measurement in the same night. Note: not all mongolian stations are on the map. I heard from trustful source that Otgon village recorded -43 during this night, which was the lowest temperature in the country

The most radical conclusion results from the comparison between the small hollow near my tent and the much bigger and deeper researched basin. It is true that it was only a single night, but as the two places are very close, the snow cover similar and the general conditions were characteristic, I am strongly inclined to believe that approximately the same thing would happen during any nights with good potential for strong thermal inversions. I also think that most of the same sized and shaped hollows (which are very common in this desert) will cool the same way as the observed one.

This case is especially interesting as the place is situated right on the saddle, not in an already cooled air mass as it would be somewhere inside the bigger basin’s endorheic sector. Most likely all that impressive “thermal plunge” came from the potential of the small scale topography. Beside these this hollow don’t even have a particularly good sky view factor, as a decent percentage of the slopes have the inclination above 20 degrees.

Snow surface temperature in the small hollow near my camp

I have three main conclusions related to the above mentioned facts:

-First is that (regarding the drainage area) size doesn’t really matter at all.

-Second is that a 8-10 meters of depth is enough to approach the maximum potential of a frost hollow. The thermal drop will happen in a more abrupt way than in the deeper basins.

-Third is that relatively steep slopes are suitable (maybe even necessary?) for fast and efficient cold air pooling, despite the altered sky view factor.

As a summary this season was a modest one without a single really good night in the researched period, but the last one’s teaching compensated me for the lack of minuses. A return to the area (hopefully with all the necessary devices this time) is likely.

Burgastyn Els, Mongolia’s highest desert (1/3)

Choosing the target

Mongolia again. All in all it’s the country with the best potential for my plans. Home to the Siberian Anticyclone’s center it offers the biggest chances to experience strong winter temperature inversions. The area is huge, the places remote and wild, relatively untouched by the modern world. The natural advantage is enhanced by the appropriate socio-political situation, where visitors can experience real freedom.

The high altitude desert with Ulaagchiin Khar lake, the track from Erdenekhairkhan village (red curve) and the location of the research area (red dot)

Two years before, while researching the sand dunes north of Erdenekhairkhan I had great luck with a powerful cold snap, when at the bottom of a 60 meters deep hollow my logger registered a stunning -53 degrees Celsius, the lowest temperature ever seen by my devices.

This year’s plan is to set the equipment in another sandy depression a little farther to the north-east, where the dunes are touching the slopes of a mountain ridge. The easternmost, respectively highest part of the desert is called “Burgastyn Els” (meaning “bushy sands”). As the desert itself has no bushes, its name’s origin must be the fact that it’s situated just below the partially bush covered mountain, which is named the same way: “Burgastyn Uul”. The chosen basin is about half the depth of the previous one, but with a bigger drainage area. With its bottom situated around 2200 meters, it’s also the highest between the sand covered hollows with considerable depth (more than 20 meters).

Actually the sand is “climbing” the mountain, as you can see the dunes continuing their eastward way on the other side through the saddles, reaching and invading the remote Ulaagchiin Khar lake. Even the 2600 meter high top has a sandy overlay.

The chosen high altitude basin with the contour intervals (1, 5, 10, 15, 24 meters) calculated on GoogleEarth

Brief summary of the research

Just a few days before the asian journey the sensor of my logger became damaged and the bad timing made impossible to repair or substitute the tackle. That meant I was constrained to leave at home also the Barani radiation shield and rely mainly on the alcohol based minimum thermometer. There will be no temperature curves, no daily maximums, only the lowest values. Fortunately this is the most important thing, so let’s be positive. I also have the digital precision device for instant measurements, which is my favorite tool while on spot.

I arrived in Mongolia in the morning of 7th January by the Budapest-Ulaanbaatar (through Istanbul) international flight. From the mongolian capital I used domestic flight to Zavkhan aimag’s capital, Uliastai. At the airport a private driver was waiting for me, who was contacted by a tourism company from Ulaanbaatar. Previously this company supported me to obtain the visa at the mongolian consulate in Budapest and helped to arrange the transports and accomodations in the country during the entire journey.

The Toyota Land Cruiser owner came from Gobi Altai province and had taken me to Erdenekhairkhan (around 85 km’s), which is the closest settlement to my targeted zone. From the village we approached the research area with the jeep, following a snow covered track (around 30 km’s) not far from the Mukhart river’s source, a scenic place with interesting geomorphology. We managed to get close to the target around 13 km’s in straight line. From this point I reached the chosen place alone by foot crossing the dune field, carrying the camping equipment and the meteorological devices in a backpack.

Even so the area is very remote, it still have some human activity in the wintertime. In contrast to the Nariyn Golin Els I didn’t saw any yurts here, only two shepherds on horseback during the entire six days of hiking through the dunes. However many horses and yaks are grazing unsupervised in the desert, many kilometers from the closest populated place.

Despite its isolation and severe climate, in most parts the surface was full with animal trails. Actually the single area which was completely lacking the domestic animals presence was the chosen frost hollow. Starting from the southern col there were only a few trails, most likely of deers.

View of the hollow from the southern col

I raised my tent near this southern saddle, around 1 km from the actual research place, at 2250 meters above sea level. The tripod with the attached minimum thermometer was set on the bottom of the frost hollow, at 2194 meters elevation (GPS on spot). During the second trip I’ve visited also the northern col, which represents the outflow point of the depression. According to my measurements the endorheic depth is 28-30 meters (about 5 meters more than GoogleEarth shows).

The tripod’s coordinates were: 48.286 N, 96.005 E. The thermometer’s elevation above the surface was around 160 cm. The instrument was measuring the minimum temperature from the afternoon of 12th January until the morning of 23th January. The precision electronic device was used to take instantaneous measurements of the air (holding the device in hand at head level while moving) and near the surface (leaving the instrument on the snow).

The tripod with the minimum thermometer on the bottom of the basin

On average the snow in the desert was rather big (for mongolian standards), reaching 20-25 cm on the bottom of the frost hollow. The weather was generally good, mostly clear or partially covered by cirrus and cirrostratus clouds, but pretty windy sometimes with some short and weak snowfall intervals. Regarding the temperatures this season wasn’t a lucky one, the clear and calm conditions were only partially covering the nights.

The research period was encompassing eleven consecutive nights. From these I spent three in my tent, the remaining ones in Erdenekhairkhan (yurt).

The devices used in the field

-One Greisinger GMH 2710-T digital precision thermometer with the measuring range between -199.9, +200 degrees Celsius, an accuracy of +-0.1 degrees Celsius and a resolution of 0.1 degrees Celsius.
-One meteorological alcohol minimum thermometer, USSR, 1988, with the measuring range between -50, +40 degrees Celsius.
-One photo camera tripod serving as the support for the instrument.

To be continued…