Which jet stream affect weather in siberia

The northern midlatitude jet stream is the right answer.  

The latitudinal position of the Northern Hemisphere jet current (NHJ) modulates the existence and recurrence of acute drought effects. Rainfall irregularities, in particular, are connected by NHJ variability; the resulting floods and aridities can have significant impacts on society and economy. This is how the northern midlatitude jet stream affects the weather condition in Siberia.

well first you need the sample of the temperature and gas level. i couldnt write a hypothesis unless i had some data. i think temperature changes will effect volumes of gas because gas changed into a solid or liquid at specific temperatures.

ok yes, but what is the question? as soon as you ask the actual question i will answer it. : )