Researchers conducted experiments to study the effects of different levels of warming on carbon dioxide, methane, and nitrous oxide emissions in alpine grassland ecosystems, quantifying changes in greenhouse gas balance. Three temperature treatments (environmental control,+1.5 ℃ temperature rise,+3.0 ℃ temperature rise) were set up in the alpine meadow in the eastern part of the Qinghai Tibet Plateau. Infrared radiation heaters were used to simulate temperature rise. The opaque box method was used to continuously measure CO ₂, CH ₄, and N ₂ O fluxes throughout the year (August 2015 to August 2016). The net ecosystem exchange (NEE) was measured during the growing season using the transparent box method. A linear mixed effects model was used to analyze the impact of warming on gas fluxes. The GWP100 (global warming potential) was used to convert CH ₄ and N ₂ O fluxes into CO ₂ equivalents and calculate the total greenhouse gas balance.

The research results indicate that: (1) A temperature increase of+3.0 ℃ significantly increases non growing season carbon dioxide emissions, leading to the transformation of ecosystems from carbon sinks to carbon sources. The increase in temperature increases methane absorption and reduces nitrous oxide emissions; (2) The alpine grassland ecosystem exhibits strong greenhouse gas positive feedback under a temperature increase of+3.0 ℃, while the impact of a temperature increase of+1.5 ℃ is relatively small; (3) The significant contribution of non growing season carbon dioxide emissions to the annual greenhouse gas balance emphasizes the importance of studying non growing season carbon cycling.

In the above study, the opaque box method was used to continuously measure the fluxes of CO ₂, CH ₄, and N ₂ O throughout the year, once every 30 minutes. The transparent box method was used to measure net ecosystem exchange (NEE) during the growing season, twice a month. An infrared radiator (Kalglo Electronics) was suspended at a height of 1.5 meters above the ground, with W1.5 and W3.0 set at 1000W and 2000W power, respectively. A non powered false heater was installed in the control area to simulate shadow effects.

The iChamber CS community whole plant carbon sink monitoring system independently developed by Ausoo Company, combined with the SmartSoil field warming test system, meets the above research needs. The iChamber CS system consists of a community whole plant automatic box or portable measurement room, AZG-LM multi gas analyzer, and the SmartSoil system consists of heating units, controllers, etc. The main technical advantages are as follows:

·Winter uniform warming: SmartSoil field warming test system adopts the method of warming in soil to ensure uniform warming, which can be used for winter warming tests.

·Temperature adjustable: Achieve a heating effect of 0.1 ℃ to 5.0 ℃ in a circular area with a diameter of 3 meters. Two heating values can be set in the heating area to achieve temperature monitoring and temperature control respectively. Heating devices can also be installed in the column to achieve synchronous regulation of moisture and temperature.

·The height can be adjusted with the growth of the plant, and the top space is constant: by adjusting the height of the box at any time, it always maintains a standard and sufficient space distance from the vegetation canopy, avoiding the "box effect". The iChamber automatic box uses a chamber without a top and is closed with a lid to reduce pressure difference.