Karagiye depression: below sea level, above human body (1/3)

Intro: sea or lake?

Despite the name, the Caspian Sea actually is a big lake, as it is completely landlocked, without a connection to the oceans. Beside its huge size (with 371000 square km is the largest lake in the world by far) owns another peculiarity: it lies 28 meters below the mean sea level. Even if it is situated in an arid climate, the salinity is much lower than in the oceans (about one third), mainly due to the fresh water influx (Volga river). Around the lake, especially in the northern sector, there is an extensive sunken plain area named “the Caspian Lowland”, a sparsely populated flatland covered with xerophyte shrubs and grass.

“Skal’naya tropa”, the rocky coast of Aktau

Centered around the oil industry, the city of Aktau lies on the eastern shore of the “sea” and is the capital of Mangystau region in south-western Kazakhstan. In the summer the climate resembles the mediterranean one (warm to hot with little rainfall), the coast being frequented by locals in the holidays. International tourism it just started to develop, hence is a great option for those travelers who want to have a unique and less crowdy beach experience. Above the specific “soviet background” (wide streets, rectangular structures, heroic memorials) the present day Aktau presents a peaceful atmosphere, trying to connect to the western standards.

Choosing the target

Compared with my usual work ethic regarding the extreme climate research, this travel wasn’t planned well ahead, instead was closer to a “last minute” decision. With less free time available I chose a somewhat “easier target”, both physically and financially.

Having a particular bonding with the lowest dry lands by a lifetime, the Karagiye Depression in south-western Kazakhstan popped up as the best choice in this more limited context. The bottom of the semi-desertic depression lies at 132 meters below the sea level, representing the lowest point of Kazakhstan (also the former Soviet Union) and position oneself fifth in the world after the Dead Sea (Israel-Jordan), Lake Assal (Djibouti), Turfan basin (China/ Xinjiang) and Qattara depression (Egypt).

The Karagiye Depression (red arrow) situated inside the Caspian Lowland (dark green, upper part of the image)

From the viewpoint of the hottest places of the Planet in the absolute sense can’t be considered a “top-notch” location, but taken into account its relatively high latitude (43 N) in the summertime has a decent delivery potential. The proximity to the coast (20-40 km) doesn’t really affect the daytime heating as the Caspian has a quite continental ambience and the sea-breeze is often completely annihilated by the dry easterly winds blowing from the inland deserts.

Soviet military topo map with Karagiye (center) and Aktau (formerly Shevchenko) in the north-west

Moderated by the sea, Aktau itself has an average summer maximum of around 31-32 degrees, with the absolute record of 44 degrees Celsius measured in the month of August (according to Wikipedia). I have no access to the weather statistics of the more inland locations in Mangystau and I’m not even sure there are real weather stations outside the regional capital in the closer surroundings.

The place has a peculiar topographical setting, being a “depression inside a depression”, as the nearby Caspian Sea itself is already situated below the level of the world ocean, while Karagiye lies another hundred meters lower than the big lake.

Satellite image with the location of the measuring equipment (red dot) in the north-eastern part of the basin

Regarding the exact location of the research I’d chosen a spot which is the farthest possible from the coast (37-38 km), while at the same time being at the lowest elevation (-132 m). Also, I’ll try to place the tripod on sandy surface, as it can slightly enhance the daytime heating compared with the more compact clay or the highly reflective salt crust (white patch in the above image).

The low-point can be reached the easiest way from the Aktau-Zhanaözen road (new turkish asphalt), from where it is about 10 km to the south, south-west, lying at the foot of the steep eastern rim of the basin.

Brief summary of the research

My plane landed in Aktau on 11th August in the early morning, just before sunrise. The optimistic forecast rushed me to reach the bottom of Karagiye and place the measuring equipment as soon as possible. Everything went fine, the locals were helpful and even if I slept close to nothing during the flight journey, the quick preparation was efficient and around 9 AM a car left me on the Zhanaözen road right at the viewpoint to the depression, from where I started the hike towards the bottom.

Descending into the Karagiye depression

Before 10 AM it was already hot, the sky completely clear and only weak wind. After meandering my way through the fragmented escarpment, I reached the flatter part and continued the walk, crossing the sometimes harder clayey, other times more squashy salty terrain with generally sparse vegetation cover. Finding a proper sandy spot on the bottom I mounted the data logger on the tripod around 12:30 PM. The exact coordinates are: 43.490923 N, 51.838903 E, the elevation -130 m. The height of the sensor from the ground is around 170 cm. At 12:42 PM the weather station started its operation. First reading: 36.6 degrees Celsius.

The weather station on the bottom of the basin

I waited near the equipment until 5 PM, to monitor the temperature rise during the hottest part of the day. The maximum reached 40.1 degrees Celsius at 4:48 PM, while I randomly measured 64.3 degrees soil temperature around 1:30 PM during the highest sun angle. Before leaving I secured the tripod attaching a sack filled with soil fragments to can handle also the windier conditions.

I’ve spent the night in a mosquito tent less than 1 km from the weather station, next to a consolidated sandy pile. Despite the clear skies, partly because of the wind, the evening was warm and the night’s minimum dropped only to 28.9 degrees Celsius. I left the research area at dawn and returned to collect the equipment four days later, on 16th August in the afternoon. During this intermediate period, beside Aktau, I travelled to other locations of the Mangyshlak peninsula (Shetpe town, Caspian coast), where encountered similar dry and hot conditions with little to no clouds.

The maximum (40.1 degrees Celsius) was reached at 4:48 PM

On 16th August I crossed the Karagiye depression, starting the hike from the other side (Kuryk road), reaching the study area after traversing the salt pan situated at the very bottom. The weather was mostly sunny but somewhat less hot than in the first day, though still far from comfortable. I found the instrument in its place and functional with all data recorded correctly. The absolute maximum surpassed by half a degree (40.6 degrees Celsius) the first days peak both on 12th and 13th, while the weakest maximum happened on 15th (36.0 degrees). The lowest value was registered on 16th in the morning, when the temperature dropped to 19.3 C, by far the coldest night.

The salt pan at -132 m

During my staying in the depression I encountered a few gazelles, camels and horses, respectively birds in the more vegetated parts. Small lizards, a few bugs and a species of spider (night time) was also present. There were no humans in the entire area between the two asphalt roads (Zhanaözen and Kuryk).

The instruments used on the field

-One LogTag UTRED30-16 data logger with the measuring range between -40 and +99 degrees Celsius, an accuracy of 0.5 degrees Celsius and a resolution of 0.1 degrees Celsius.

-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 photo camera tripod serving as the support for the instruments.

-One helical solar radiation shield from Barani Design Technologies: https://www.baranidesign.com/

Soil temperature around noon

To be continued…

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