本文選題：碳循環(huán)　切入點(diǎn)：溫室氣體交換　出處：《中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院東北地理與農(nóng)業(yè)生態(tài)研究所)》2017年博士論文

【摘要】：IPCC報(bào)告指出,北方高緯地區(qū)是氣候變化敏感區(qū),氣候變化對(duì)該地區(qū)水熱條件影響顯著,近幾十年來(lái),全球溫度的上升造成該地區(qū)多年凍土的持續(xù)退化。北方高緯泥炭沼澤碳儲(chǔ)量占全球土壤碳庫(kù)的1/3,在氣候變化的作用下,北方高緯泥炭沼澤有可能從碳匯轉(zhuǎn)化成為碳源,對(duì)氣候變化起到反饋?zhàn)饔谩Ｄ壳瓣P(guān)于氣候變化對(duì)北方高緯泥炭沼澤碳循環(huán)影響的研究還很薄弱。因此,本研究選取大興安嶺多年凍土泥炭沼澤為研究對(duì)象,采用渦度協(xié)方差法,對(duì)生態(tài)系統(tǒng)二氧化碳(CO_2)和甲烷(CH_4)交換通量進(jìn)行連續(xù)定點(diǎn)觀測(cè),通過(guò)對(duì)數(shù)據(jù)的整合分析,探究從日變化到季節(jié)變化尺度地-氣間CO_2和CH_4交換的規(guī)律,分析不同時(shí)間尺度的環(huán)境控制因子,改進(jìn)和完善現(xiàn)有統(tǒng)計(jì)模型,模擬不同時(shí)間尺度地-氣間CO_2和CH_4交換,并根據(jù)增溫實(shí)驗(yàn)的情境,預(yù)測(cè)增溫對(duì)大興安嶺多年凍土泥炭沼澤地-氣間CO_2和CH_4交換的影響。本研究主要有以下幾方面的進(jìn)展:1在渦度協(xié)方差法數(shù)據(jù)處理方面:以通量貢獻(xiàn)區(qū)和湍流穩(wěn)定性作為控制條件,采用更加嚴(yán)格的通量數(shù)據(jù)質(zhì)量控制標(biāo)準(zhǔn),建立通量數(shù)據(jù)篩選方案,能夠顯著提高了觀測(cè)數(shù)據(jù)質(zhì)量,減少觀測(cè)數(shù)據(jù)總體不確定性。采取這種處理方法,能夠揭示更高時(shí)間分辨率下地-氣間CO_2和CH_4交換的規(guī)律,發(fā)現(xiàn)CH_4交換的日間變化規(guī)律呈現(xiàn)單峰分布趨勢(shì),CO_2交換在午前和午后呈現(xiàn)不同的光響應(yīng)趨勢(shì)。除此之外,地-氣間CH_4通量呈現(xiàn)一定程度的空間差異性。2揭示了多年凍土泥炭沼澤地-氣間CH_4交換通量的變化特征和環(huán)境控制因子:2014年和2015年生長(zhǎng)季觀測(cè)到CH_4交換通量的波動(dòng)范圍分別為1.8~40.2 mg CH_4 m-2 d-1和-3.9~15.0 mg CH_4 m-2 d-1。CH_4通量與深層(15 cm及以下)土壤溫度、融深顯著相關(guān)。據(jù)估計(jì),2014年和2015年生長(zhǎng)季后半段CH_4釋放分別占整個(gè)生長(zhǎng)季釋放量的77.9%和85.9%。將標(biāo)準(zhǔn)化的融深作為模擬CH_4交換通量的控制系數(shù)加入指數(shù)型溫度響應(yīng)模型能夠有效提高多年凍土泥炭沼澤CH_4通量模擬準(zhǔn)確度。CH_4通量的季節(jié)變化受到多年凍土由表層到深層逐層進(jìn)行的季節(jié)性融化特征以及季節(jié)性溫度變化共同控制。強(qiáng)降水事件和生長(zhǎng)季總降水量分別對(duì)CH_4通量的短期變化和CH_4釋放的年際差異有顯著性影響。3揭示了多年凍土泥炭沼澤地-氣間CO_2交換通量的變化特征和環(huán)境控制因子:經(jīng)典光響應(yīng)方程適用于模擬研究區(qū)植被光合速率,在日變化尺度上高強(qiáng)度光照可能導(dǎo)致植物光合能力的降低,描述光合和呼吸速率的參數(shù)在季節(jié)變化的尺度上呈現(xiàn)顯著的單峰分布趨勢(shì)。與呼吸速率的溫度響應(yīng)方程相結(jié)合,利用改進(jìn)的CO_2交換模型,模擬日CO_2凈交換量波動(dòng)范圍在-4.42 g C m-2 d-1和2.90 g C m-2 d-1之間,2014年和2015年生長(zhǎng)季(5月19日~10月8日)吸收量分別為78.35 g C m-2和90.07 g C m-2。表觀光能利用率最大約為0.049 mol CO_2 mol photon-1,生態(tài)系統(tǒng)理論光合速率上限約為27.24μmol CO_2 m-2 s-1,而系統(tǒng)能夠達(dá)到的CO_2凈最大交換通量約-15μmol CO_2 m-2 s-1。每個(gè)生長(zhǎng)季8月中下旬,系統(tǒng)由碳匯逐漸向碳源轉(zhuǎn)化。4預(yù)測(cè)了在增溫的情境下多年凍土泥炭沼澤CO_2交換通量的變化趨勢(shì):被動(dòng)增溫系統(tǒng)能夠模擬變暖條件下環(huán)境因子的變化趨勢(shì),根據(jù)被動(dòng)增溫系統(tǒng)內(nèi)環(huán)境數(shù)據(jù)記錄,開(kāi)頂箱內(nèi)部氣溫和5 cm土溫平均分別上升約0.81°C和2.42°C。根據(jù)這一情境,模擬氣候變化條件下多年凍土泥炭的響應(yīng)特征,系統(tǒng)的碳源特征逐漸減弱,至氣溫上升0.67oC,對(duì)應(yīng)土壤溫度上升約2.0oC時(shí),估算全年尺度上多年凍土泥炭轉(zhuǎn)化為凈CO_2源,而當(dāng)氣溫上升約1.0oC,土壤溫度上升約3.0oC時(shí),生態(tài)系統(tǒng)在生長(zhǎng)季內(nèi)向凈CO_2源轉(zhuǎn)化。
[Abstract]:IPCC report pointed out that the northern high latitude region is sensitive to climate change, the impact of climate change on the water and heat conditions in the region significantly, in recent decades, the global temperature rise caused by the continued degradation of the permafrost area. Northern high latitude peatlands carbon reserves accounted for 1 of the global soil carbon pool in /3, the effects of climate change. The northern high latitude peat swamp likely from carbon sequestration into carbon source, to a feedback effect on climate change. The research on climate change in the northern high latitude peatlands carbon cycle effect is very weak. Therefore, this study selected Greater Khingan Range permafrost peat as the research object, using the eddy covariance method, the ecological system of carbon dioxide (CO_2) and methane (CH_4) fluxes for continuous observation, through the integration of data analysis, the inquiry from the daily change to seasonal scale gas exchange between CO_2 and CH_4. Law, control factor analysis of different time scale environment, improve and perfect the existing statistical model, simulation of different time scales between CO_2 and CH_4, gas exchange, and according to the warming experiment situation, predicting warming on permafrost in Greater Khingan Range peat bog - gas between the CO_2 and CH_4 exchange effect. This research progress the following aspects: 1 in the aspect of data processing method: the eddy covariance flux contribution and turbulence stability as the control condition, the flux data quality control more stringent standards, establishing a flux data screening scheme, can significantly improve the quality of observation data, reduce the data overall uncertainty. This processing method can reveal the higher time resolution under the CO_2 and CH_4 gas exchange rules, find that the daily variation of CH_4 exchange of unimodal distribution trends, CO_2 exchange in morning and afternoon The different light response trend. In addition, gas CH_4 fluxes showed.2 spatial difference to a certain extent reveals the permafrost peat bog - gas between CH_4 flux variations and environmental control factors: 2014 and 2015 growing season observed CH_4 flux in the wave range were 1.8~40.2 mg CH_4 m-2 D-1 and -3.9~15.0 mg CH_4 m-2 d-1.CH_4 flux and deep (15 cm and below) soil temperature, thawing depth was significantly correlated. It is estimated that in 2014 and 2015 growth season CH_4 release accounted for the whole growth season, the release amount of 77.9% and 85.9%. will control the standardized coefficient of thawing depth as the simulated CH_4 exchange flux added index temperature response model can effectively improve the seasonal variation of permafrost peat CH_4 flux simulation accuracy of.CH_4 flux by permafrost from the surface to the deep layer by layer seasonal melting The common control characteristics and seasonal change of temperature and precipitation events. The growth of Ji Zong precipitation of short-term changes and CH_4 release of the annual variation of CH_4 flux has a significant impact.3 reveals the permafrost peat bog - gas change between the environment and the characteristics of CO_2 flux control factor: classical optical response equation is used to simulate the study on vegetation photosynthetic rate, diurnal changes in scale of high intensity light may cause the decrease of photosynthetic capacity of the plant, description parameters of photosynthetic and respiration rate showed a single peak distribution trend significant seasonal changes in scale. The equation combined with the respiration rate of the temperature response, exchange model using the improved CO_2 Simulation on the net CO_2 exchange volume fluctuation in the range between -4.42 g C m-2 D-1 and 2.90 g C m-2 D-1, in 2014 and 2015 growing season (May 19th ~10 8) uptake were 78.35 g and 90.07 g C m-2 C m-2. apparent light use rate is about 0.049 mol CO_2 mol photon-1, the ecological system theory of photosynthetic rate limit is about 27.24 mol CO_2 m-2 S-1 CO_2, and the system can reach the maximum net flux of about -15 mol CO_2 m-2 s-1. in each growing season 8 months late, the system consists of carbon sinks gradually to the carbon source conversion of.4 to predict the variation trend in the context of increasing temperature in permafrost peat swamp CO_2 exchange: passive warming system can simulate warming trend of environmental factors under the condition of increasing environmental temperature according to the passive data recording system, open top gas temperature and 5 cm temperature respectively increased by about 0.81 DEG C and 2.42 DEG C. according to this situation, the simulation response characteristics under the condition of climate change in permafrost peat, carbon source and characteristics of the system gradually weakened, and temperature rise of 0.67oC, the corresponding soil temperature rise of about 2.0oC, estimated the annual scale more The peat of permafrost is converted into a net CO_2 source, but when the temperature rises about 1.0oC and the soil temperature rises about 3.0oC, the ecosystem converts to the net CO_2 source in the growing season.

【學(xué)位授予單位】：中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院東北地理與農(nóng)業(yè)生態(tài)研究所)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：X171;X16

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本文編號(hào)：1716278