According to Vaultedwatches.com, Mongolia is a vast region of Central Asia (in cin. Mêng – ku), comprised between the Saians and the Transbaicalia mountains to N., Manchuria and the Chinese lowland to E., the Nan-shan (Richthofen Mountains) and the Great Wall in S., open to the west towards the Tarim and Zungaria basins. Its extension is estimated at 2,700,000 sq km; the average altitude fluctuates in the various parts from 1000 to 1600 m. Politically it is divided into Inner and Outer Mongolia; this is still under the administrative and military control of China: Outer Mongolia was erected, in 1924, as an independent state organized on the model of the Soviet republics.
Climate. – The climate, extremely continental, is characterized by very strong temperature variations, both annual and diurnal, by violent winds and by a great scarcity of rainfall, which in northern and central Mongolia does not reach 200 mm. nodded. The region, close to the Siberian zone of high winter pressures, is swept, especially in winter, by the harsh and dry winds of the NW. During the summer, winds from the E. and NE sometimes also blow. which can bring rain to northeastern Mongolia. The annual average temperatures are very low (Urga −2 ° 4; Uliassutai −0 ° 2), given the extraordinarily cold winters. The average January temperature is in fact -26 ° 2 in Urga; of -24 ° 2 to Uliassutai, which, despite being higher and more internal, has an average of the coldest month somewhat less raw, perhaps due to influence of the dry anticyclonic winds that warm up a bit as they descend along the sides of the mountains. Summers are relatively hot: the average temperature in July is 17 ° 5 in Urga; of 19 ° 2 in Uliassutai, and much higher in the southern Gobi, where in Alaska there is a normal annual temperature fluctuation from + 38 ° to −33 ° and very strong diurnal excursions (up to 40 °). Winters are very long: the rivers of northeastern Mongolia remain frozen from November to April and even the Hwangho, in its northern elbow, remains frozen from mid-November to mid-March. The scarce rains all fall in summer; the wettest months are July and August, during which it can sometimes rain for 2-3 days in a row. On the other hand, winters are dry and snowless and almost calm, unlike summers, during which very frequent, especially in the Gobi, are the very strong dry storms coming from the NO. dragging large quantities of sand towards the S. in frightening trumpets.
Hydrography. – Hydrography is reduced to a few watercourses with limited basins and to a region of small lake basins located in the mountainous territory of the north-west (valley of the lakes). The rest of the country, including all the central-southern part (Gobi desert), is devoid of surface water.
The main river, the Selenga, originates with the name of Eder, in the north-west of Uliassutai and up to the confluence with the Chulutu, which comes from the south, retains this name; it continues, therefore, with that of Selenga up to the Siberian border, which it reaches after 530 km. of course and after another 400 km. it flows into Lake Baikal. Of its tributaries, the main one is the Orkhon, 840 km long; historically notable river for having on the left bank Qaraqorum, the ancient capital of the Mongol empire; a tributary of the Orkhon, the Tūla, bathes Urga and is born at the foot of the Kentei mountains.
In the mountainous region of the north-west is the basin of the upper Jenissei sponsored by the two main courses of Bei-kem (300 km.) And Khua-kem (475 km.), Which join with Khem-belder to give rise to the ‘Ulu-kem that after a journey of about 200 km. receives the Kemchik and enters Siberia with the name of Jenissei, between rapids and locks. This whole region is characterized by tiers: from Siberia the ground rises with large terraces, sown with lakes and swept by violent winds, up to the Kobdo region. Of these lakes, the largest is Koso-gol, with an area of 300 sq. Km., Located on one of these steps, at 1600 m. high, from which it dominates the underlying platform of Dorja-nōr, on the high Khuakem. Followed by the Ubsa-nōr, or lake of otters, at 722 m., The Kirghisnōr, at 1000 m., The Qarausu-nōr, at 1760 m. These lakes are joined by important rivers: the Tess (600 km.), The Dzapkhin (760 km.), The Kobdo (540 km.), Etc. Their arrangement and their connection seem to be destined to a union with Jenissei, but this communication is prevented by the imposing bastion of Tannu-ola, from which their basin is closed.
The most important watercourse in the north-east is the Kerulen (1200 kilometers). 20 to 40 m wide, without tributaries, 2 m deep. when it is full, it flows in an isolated valley in the desert ending in the Dalai-nōr, a lake with marshy shores at 500 meters above sea level.