塔里木河下游胡杨群落CO2通量特征与水分利用效率

以极端干旱环境中的胡杨群落为研究对象,利用涡度相关通量观测系统,研究了胡杨群落CO_2通量与水分利用效率在不同物候期的动态规律。结果表明:胡杨CO_2通量在不同物候期日变化趋势基本一致,但存在明显的季节差异,其中果熟期CO_2通量变化幅度最大,开花期最小,展叶期介于二者之间。相关分析表明,胡杨群落CO_2通量均与显热通量、潜热通量、动量通量、土壤热通量、净辐射以及空气相对湿度呈极显著相关。其中,净辐射、潜热通量和显热通量与CO_2通量的相关系数较大,其变化范围分别为-0.82—-0.88、-0.64—-0.66和-0.63—-0.94,是影响群落CO_2通量的最主要环境因子。胡杨群落水分利用效率(WUE)同样存在明显日变化规律。其时间动态表现为:群落水分利用效率在开花期、叶黄期和落叶期变化幅度大,开花期最高,在展叶期和果熟期WUE最稳定。净辐射和风速是影响群落水分利用效率的两个最关键要素。     

Characteristics of water and carbon fluxes during growing season in three typical arid ecosystems in central Asia

亚洲中部干旱区地处欧亚大陆腹地, 干旱少雨, 生态环境十分脆弱, 研究该地区大气与地表之间的能量和物质交换对干旱区水资源利用和生态环境保护具有重要意义。该文分析了亚洲中部干旱区荒漠与草地生态系统能量、水汽和CO₂通量的日变化及季节变化特征, 探究了水汽和CO₂通量对主要环境因子的响应。通过分析亚洲中部干旱区3个站点的涡度相关资料发现: 亚洲中部干旱区荒漠和草地生态系统在生长季(4-10月)能量、水汽通量、净CO₂通量和总初级生产力的日变化呈“单峰型”, 而荒漠生态系统呼吸日变化相对稳定; 草地生态系统白天的潜热通量占净辐射通量的比例明显高于荒漠生态系统; 草地生态系统在5-8月呈现较强的碳汇, 而荒漠生态系统表现为弱碳汇。亚洲中部干旱区草地和荒漠生态系统水汽通量和总初级生产力对降水、净辐射通量或光合有效辐射、饱和水汽压差、气温均表现出明显的敏感性。     

亚洲中部干旱区3个典型生态系统生长季水碳通量特征

亚洲中部干旱区地处欧亚大陆腹地, 干旱少雨, 生态环境十分脆弱, 研究该地区大气与地表之间的能量和物质交换对干旱区水资源利用和生态环境保护具有重要意义。该文分析了亚洲中部干旱区荒漠与草地生态系统能量、水汽和CO₂通量的日变化及季节变化特征, 探究了水汽和CO₂通量对主要环境因子的响应。通过分析亚洲中部干旱区3个站点的涡度相关资料发现: 亚洲中部干旱区荒漠和草地生态系统在生长季(4-10月)能量、水汽通量、净CO₂通量和总初级生产力的日变化呈“单峰型”, 而荒漠生态系统呼吸日变化相对稳定; 草地生态系统白天的潜热通量占净辐射通量的比例明显高于荒漠生态系统; 草地生态系统在5-8月呈现较强的碳汇, 而荒漠生态系统表现为弱碳汇。亚洲中部干旱区草地和荒漠生态系统水汽通量和总初级生产力对降水、净辐射通量或光合有效辐射、饱和水汽压差、气温均表现出明显的敏感性。     

季节性干旱对中亚热带人工林显热和潜热通量日变化的影响

植被与大气间的显热和潜热通量的日变化是大气过程和植被生理过程的显著标志。本研究利用ChinaFLUX千烟洲站典型的夏季雨热不同季的季节性干旱的试验条件,探讨了2003年季节性干旱对该生态系统显热和潜热通量日变化变异幅度和峰值时间的影响。研究表明：显热通量的日变化变异幅度年平均值为176 W/m2。潜热通量的日变化变异幅度年平均值为171 W/m2。显热通量到达日变化峰值的时间平均为11:57。全年潜热通量的日变化都在午后达到峰值,平均值为12:33。季节性干旱造成显热通量的日变异幅度明显增大,从144W m-2增加到321 W m-2。而潜热通量的日变异幅度明显降低,从324 W/m2减小到198 W/m2。,显热和潜热通量日变异幅度的相对变化明显增大,从-165 W/m2增加到76 W/m2,气温和饱和水汽压差是影响显热和显热日变异幅度及其相对变化的主要控制因素。干旱胁迫期,深层水对显热通量日变化变异幅度及其与潜热通量日变化变异幅度的相对变化的作用更显著,而潜热通量日变化变异幅度与气象要素关系不显著。季节性干旱造成显热通量日变化的峰值时间和显热和潜热通量日变化峰值时间的相对变化明显向下午偏移,显热通量日变化的峰值从上午11:31到中午12:17,相对变化从1小时到1小时20分钟。季节性干旱对潜热通量日变化峰值时间没有显著的影响。非干旱胁迫期,显热通量日变化峰值时间和显热及潜热通量日变化峰值时间的相对变化均与气温负相关,而干旱胁迫期,则与气温正相关。潜热通量日变化峰值时间与气象要素关系均不显著。该生态系统显热和潜热通量日变化峰值的相对变化主要受降水量的季节分配控制,在干旱胁迫期降水的作用更加明显。潜热和显热通量日变化峰值时间的相对变化总体上都受植被与大气间的耦合程度控制。     

内蒙古温带荒漠草原生态系统水热通量动态

基于2008年全年内蒙古温带荒漠草原的水热通量观测数据,对荒漠草原水、热通量的日、季动态进行了分析.结果表明：温带荒漠草原感热通量和潜热通量的日动态均呈单峰型曲线,在12:00-13:30左右达最大值,其与地表净辐射的日变化趋势基本一致,但感热和潜热的峰值出现时间较地表净辐射峰值出现时间滞后约1 h;温带荒漠草原感热通量和潜热通量的日累积最大值分别为319.01和425.37 W·m^-2,分别出现在5月30日和6月2日;月均感热通量与潜热通量的最大值分别出现在5月和6月,最小值分别出现在1月和12月.研究区土壤含水量与降水的相关性较好,表层土壤含水量对降水的反应最敏感,深层土壤水分对降水的反应存在位相滞后.感热通量和潜热通量的季节动态与地表净辐射基本一致,均受降水影响.感热通量受地表净辐射的影响明显,而潜热通量对降水的反应较敏感,且土壤含水量在潜热通量中起主要作用.     

玉米农田水热通量动态与能量闭合分析

 基于锦州农田生态系统野外观测站玉米农田涡度相关系统近2年的水热通量观测数据，分析了玉米农田水热通量的日际、年际变化特征及其能量 平衡状况。结果表明： 1）玉米农田水热通量日变化与年变化均呈单峰型二次曲线，峰值出现在12∶00～13∶00左右，与净辐 射的日变化、年 变化同步，潜热通量最大可达到655 w•m^－2（出现在2004年7月8日1 3∶00），显热通量最大值大约为369 w•m^－2（出现在2004年5月31日13∶ 00）。2）玉米农田水热通量强度与局地的环境条件密切相关：显热通量与大气压的年变化呈负相关，潜热通量与气温年变化呈正相关。水热通 量受降水的影响较大，对降水的反应较敏感。其中，潜热通量(LE)不仅与降水的强度有关，而且随着降水的季节分布的不同而出现不同的响应 ，即使同样量级的降水在夜间与白天对LE的影响也是不同的。3）玉米农田通量观测呈现能量不闭合现象，主要原因可能是未包含0～5 cm土壤 热储量与冠层热储量，造成大约15.5%的能量损失。     

梭梭(Haloxylon ammodendron)生理与个体用水策略对降水改变的响应

随着全球变化的加剧,降水改变正导致荒漠生态系统中植物用水策略的适应性变化;对降水变化响应的种间差异性影响着荒漠植物群落组成。研究将生理生态与个体形态尺度相结合,调查中亚荒漠关键种梭梭Haloxylon ammodendron对降水变化导致的自然生境中水分条件改变的响应与适应。实验于2005年生长期开展,在古尔班通古特沙漠南缘原始盐生旱生荒漠中设置3个降水梯度（自然、双倍和无降水）;观测并比较不同降水条件下光合作用、蒸腾作用、叶水势、水分利用效率、地上生物量累积和根系分布的变化。结果表明,梭梭主要利用降水形成的浅层土壤水维持生存;有效的形态调节和较强的气孔控制是其维持光合能力以及适应降水变化的主要机制;降水增多对其产生正效应,预示着梭梭可能在未来种间竞争和群落演替中占有优势。     

高效经营雷竹林生态系统能量通量过程及闭合度

利用开路涡度相关系统和常规气象仪,对高效经营的雷竹林生态系统2011年的显热通量、潜热通量、净辐射、土壤热通量以及气温、地温、降雨量进行了观测,分析该生态系统能量通量的变化,以及各能量分量的分配特征,并计算了波文比及能量闭合.结果表明：雷竹林全年净辐射为2928.92 MJ·m^-2,潜热通量、显热通量和土壤热通量分别为1384.90、92754和-28.27 MJ·m^-2,各能量分量的日变化和月变化基本呈单峰曲线.潜热通量为能量散失主要形式,占净辐射的47.3%,显热通量占31.7%,波文比呈“U”型曲线,在0.285～2.062之间变化,土壤为热源.雷竹林年能量闭合度为0.782,月平均闭合度为0.808.
     

亚热带毛竹林生态系统能量通量及平衡分析

利用开路涡度相关系统和常规气象观测仪器,对亚热带(浙江省)毛竹林生态系统2011年的净辐射、显热通量、潜热通量、土壤热通量以及气温、地温、降雨量等气象要素进行了连续观测,定量分析了毛竹林生态系统能量通量的变化和各能量分量的分配特征,并计算了能量闭合度以及波文比。结果表明:毛竹林全年净辐射为2628.00 MJ/m2,显热通量为576.80 MJ/m2,潜热通量为1666.77 MJ/m2,土壤热通量为-7.52 MJ/m2,土壤为热源,各能量分量季节变化明显,日变化基本呈单峰型曲线变化。显热通量占净辐射的22.0%,潜热通量占63.4%,毛竹林生态系统潜热通量为能量散失的主要形式。波文比逐月变化规律不明显,波动较大,在0.07—1.77之间变化,能量平衡比率法得出毛竹林年能量闭合度为0.85,月平均闭合度为0.84,能量闭合度高于线性回归法计算结果,但仍有15%的能量不闭合。     

我国亚热带毛竹林生长季能量通量过程及闭合度分析

为探讨我国亚热带毛竹林(Phyllostachys edulis)生长季的能量平衡关系,利用开路涡度相关法,对2011年毛竹林生长季的能量通量的变化特征进行了研究,并应用能量平衡比率法和线性回归2种方法,分析了能量闭合的特点。结果表明,我国亚热带毛竹林生长季的净辐射总量为1738.2 MJ m–2,显热通量为354.3 MJ m–2,潜热通量为1146.0 MJ m–2,土壤热通量为58.9 MJ m–2,土壤为热汇,显热通量占净辐射的20.4%,潜热通量占65.9%,土壤热通量占3.4%。毛竹林生长季的能量闭合度为0.89,月平均闭合度为0.91,但仍有11%的能量不闭合。可见,毛竹林生长季以潜热能量散失形式为主,各能量分量均以净辐射变化为基础,且日变化基本呈单峰型曲线。     

内蒙古温带荒漠草原能量平衡特征及其驱动因子

基于内蒙古苏尼特左旗温带荒漠草原生态系统观测站2008年全年的涡度相关观测与相应的生物、环境观测资料,对生态系统能量平衡特征及其驱动因子分析表明:能量平衡各分量(净辐射,Rn;感热通量,H;潜热通量,LE;土壤热通量,G)呈单峰型日动态,白天大部分时间H/RnG/RnLE/Rn;夜间G/Rn占主导;全天LE/Rn相对较小,即使在植物生长盛期。较低的LE/Rn可能与荒漠草原气候干旱及植被分布稀少有关。日Rn受天气变化的影响,特别是在雨季,Rn日间差异较大,呈现锯齿状波动。能量平衡各分量季节变化明显,Rn、H、LE和G最大月分别为7、5、6月份和6月份。全年H是Rn的主要能量支出项(58%);LE其次(26%),年蒸散量(190.3mm)大于年降水量(136.3mm),与多年平均降水量接近(183.9mm),其中最大日蒸散率3.8mm/d;G所占比例较小(1%),全年基本保持平衡。然而G白天吸收能量,夜间释放能量;夏季储存能量,冬季释放能量的特点,在能量平衡中存在类似"能量缓存"的作用,不能被忽略。降水过程显著影响内蒙古温带荒漠草原水热交换。降水后较降水前LE峰值明显增大,而H峰值降低。日蒸散率峰值多数与降水事件有关。而且,生长季日蒸散率波动与降水引起的SWC变化趋势一致。生长季潜热分配(LE/Rn)主要受到土壤含水量(SWC)、饱和水汽压差(VPD)及叶面积指数(LAI)共同影响。LE/Rn随SWC增大呈增加趋势,LE/Rn随VPD增大而降低,LE/Rn随LAI增大呈二次曲线变化。其中LAI为0.2m2/m2是一个阈值,当LAI0.2m2/m2,SWC是LE/Rn主要驱动因子;当LAI0.2m2/m2,SWC和LAI共同驱动LE/Rn。应用退耦因子(Ω)评价了荒漠草原与大气之间水汽交换的耦合状况。与其他草原类型相比,本研究区退耦因子(Ω)相对较低(生长季平均0.15)。生长盛期Ω相对较高,Rn是LE的主导因子;而生长前期和后期Ω相对较低,VPD是LE的主要控制因子。     

鼎湖山针阔混交林旱季能量平衡研究

运用涡度相关(Eddycovariance,EC)法开路系统、常规微气象观测系统及土壤热通量板等设施对鼎湖山季风常绿阔叶林旱季(2003／1／9—2003／1／23)的能量分量进行测定。结果表明,平均净辐射通量(Net radiation,Rn)为53．14Wm^2,与下行短波辐射具有相同的变化趋势。林冠上层EC法潜热通量(Latent heat,LE)、显热通量(Sensible heat,Hs)实测平均值分别为57．18Wm^-2,43．40Wm^-2,林冠下层分别为12．61Wm^-2、7．61Wm^-2。白昼EC法所测得的LE和Hs数据与利用波文比．能量平衡法(Bowen ratio and energy balance,BREB)计算出的数据相比,略偏低,而夜间及凌晨数据差异较大。土壤热通量日变化曲线呈“S”形,平均土壤热通量为．1．50Wm^-2,表面土壤总热通量(Gt)仅为5cm处土壤热通量的84．0％,可见表层土壤尽管很薄,但其热储量不能忽略。将LE、Hs之和与可供能量(Rn—Gt)进行闭合,回归直线斜率为0．9128,相关系数达0．8517,与许多研究结果的60％-90％的区间相符,这说明鼎湖山涡度相关法通量观测数据是非常可靠的。     

东北阔叶红松林能量平衡特征

采用涡度相关法,结合小气候观测,对东北阔叶红松林的能量平衡特征进行了研究。结果表明,森林全年获得的辐射能量为2.3×109J/m2,平均净辐射(Rn)强度为72.1 W/m2,12月最小,平均为5.8W/m2,6月最大,平均为127 W/m2。除了受太阳高度角的支配,Rn对中小尺度天气变化响应显著。非生长季,森林主要能量支出项为感热通量(H),约占Rn的72%,H最大值出现在5月份;生长季,主要能量支出项为潜热通量(LE),约占Rn的60%,LE最大值出现在7月份。全年因蒸散消耗的能量为1.2×109J/m2,占净辐射的52%,森林蒸散的水量为493mm,占降水量的88%。波文比β近似呈U字型变化,其值受森林物候变化影响显著,在非生长季平均值约为3.0,生长季为0.5左右。土壤热通量(G)在非生长季表现为能量平衡方程的收入项,约占有效能量的5.0%;生长季表现为支出项,约占有效能量的4.0%,其变化过程与土壤温度梯度及叶面积指数密切相关。长白山通量观测站能量平衡收支闭合度为86%,不闭合的原因有待于进一步的研究。     

Performance evaluation of the SITE® model to estimate energy flux in a tropical semi-deciduous forest of the southern Amazon Basin

The SITE® model was originally developed to study the response of tropical ecosystems to varying environmental conditions. The present study evaluated the applicability of the SITE model to simulation of energy fluxes in a tropical semi-deciduous forest of the southern Amazon Basin. The model was simulated with data representing the wet and dry season, and was calibrated according to each season. The output data of the calibrated model [net radiation (Rn), latent heat flux (LE) and sensible heat flux (H)] were compared with data observed in the field for validation. Considering changes in parameter calibration for a time step simulation of 30 min, the magnitude of variation in temporal flux was satisfactory when compared to observation field data. There was a tendency to underestimate and overestimate LE and H, respectively. Of all the calibration parameters, the soil moisture parameter presented the highest variation over the seasons, thus influencing SITE model performance.     

Effect of the replacement of a native savanna by an African Brachiaria decumbens pasture on the CO2 exchange in the Orinoco lowlands,Venezuela

In the Orinoco lowlands, savannas have been often replaced by pastures composed of the C₄ grass, Brachiaria decumbens Stapf. We addressed following questions: (1) How does the replacement of the native vegetation affect CO₂ exchange on seasonal and annual scales? (2) How do biophysical constraints change when the landscape is transformed? To assess how these changes affect carbon exchange, we determined simultaneously the CO₂ fluxes by eddy covariance, and the soil CO₂ efflux by a chamber-based system in B. decumbens and herbaceous savanna stands. Measurements covered a one-year period from the beginning of the dry season (November 2008) to the end of the wet season (November 2009). During the wet season, the net ecosystem CO₂ exchange reached maximum values of 23 and 10 μmol(CO₂) m^?2 s^?1 in the B. decumbens field and in the herbaceous savanna stand, respectively. The soil CO₂ efflux for both stands followed a temperature variation during the dry and wet seasons, when the soil water content (SWC) increased above 0.087 m³ m^?3 in the latter case. Bursts of CO₂ emissions were evident when the dry soil experienced rehydration. The carbon source/sink dynamics over the two canopies differed markedly. Annual measurements of the net ecosystem production indicated that the B. decumbens field constituted a strong carbon sink of 216 g(C) m^?2 y^?1. By contrast, the herbaceous savanna stand was found to be only a weak sink [36 g(C) m^?2 y^?1]. About 53% of the gross primary production was lost as the ecosystem respiration. Carbon uptake was limited by SWC in the herbaceous savanna stand as evident from the pattern of water-use efficiency (WUE). At the B. decumbens stand, WUE was relatively insensitive to SWC. Although these results were specific to the studied site, the effect of land use changes and the physiological response of the studied stands might be applicable to other savannas.     

内蒙古克氏针茅草原生态系统-大气通量交换特征

基于内蒙古克氏针茅草原生态系统的涡动相关观测资料和小气候梯度系统观测资料,对研究区碳通量和水热通量的日、季动态进行了研究.结果表明：克氏针茅草原生态系统生长季的碳通量日动态呈U型曲线,即日出前释放CO₂,日出后开始吸收CO₂,正午前后达峰值,午后吸收CO₂减弱,日落后重新转为释放CO₂;9月白天CO₂吸收最为强烈,8月次之,10月最低.克氏针茅草原的感热和潜热通量的日动态均呈倒U型曲线,与碳通量日动态相反,即白天感热和潜热通量多为正值,夜间感热为负值,潜热接近于零;感热通量以5月最高,潜热通量以9月最高.冬季草地为弱碳源,CO₂通量较小,夏季表现为明显的碳汇.     

城市公园绿地水、热与CO2通量观测与分析

水、热和CO2通量是评价城市绿地生态效益的重要指标。在北京海淀公园中部和边缘架设涡度相关系统,连续观测和定量研究城市公园绿地影响下的通量变化特征。结果表明,公园绿地所获得的净辐射在植被生长季节大部分用于植被的蒸散作用,潜热大于显热;而在植被非生长季节大部分用于显热,潜热数值非常小。晴天显热与潜热的比值在春季随着植被枝叶的生长逐渐减少,到夏季达到最小值约1/3,在秋季随着植被叶片枯黄逐渐变大,冬季达到数倍。公园绿地能量平衡率在52%～83%,普遍存在能量不平衡。公园中部的潜热观测值大于公园边缘,而显热小于公园边缘;公园中部CO2通量日均值为负,公园绿地是CO2汇。公园绿地在植被生长季节具有明显的降温增湿、吸收CO2等生态效应。     

Light and water-use efficiencies of pine shoots exposed to elevated carbon dioxide and temperature

An automatic gas exchange system was used to continuously measure water and carbon fluxes of attached shoots of Scots pine trees (Pinus sylvestris L.) grown in environment-controlled chambers for a 3-year period (1998-2000) and exposed to either normal ambient conditions (CON), elevated CO2 (+350 micro mol mol-1; EC), elevated temperature (+2-6 degrees C; ET) or a combination of EC and ET (ECT). EC treatment enhanced the mean daily total carbon flux per unit projected needle area (Fc.d) by 17-21 %, depending on the year. This corresponds to a 16-24 % increase in light-use efficiency (LUE) based on incident photosynthetically active radiation. The EC treatment reduced the mean daily total water flux (Fw.d) by 1-12 %, corresponding to a 13-35 % increase in water-use efficiency (WUE). The ET treatment increased Fc.d by 10-18 %, resulting in an 8-19 % increase in LUE, and Fw.d by 48-74 %, resulting in a reduction of WUE by 19-34 %. There was no interaction between CO2 and temperature elevation in connection with either carbon or water fluxes, as the carbon flux responded similarly in both ECT and EC, while the water flux in the ECT treatment was similar to that in ET. Regressions indicated that the increase in maximum LUE was greater with increasing air temperature, whereas changes in WUE were related only to high vapour pressure deficit. Furthermore, changes in LUE and WUE caused by ECT treatment displayed strong diurnal and seasonal variation.     

长白山阔叶红松林生长季热量平衡变化特征

根据长白山阔叶红松林2001年5月下旬至10月上旬微气象梯度观测资料和辐射、土壤热通量资料,用波文比-能量平衡方法(BREB方法)计算了森林的显热通量和感热通量,并计算了森林大气和植被体的储热量,分析了阔叶红松林热量平衡各项的日变化和季节变化,结果发现,热量平衡(净辐射)与太阳总辐射呈线性关系;热量平衡各项都与净辐射有相同的日变化特征,为昼正夜负的曲线．各项的绝对值一般表现为净辐射>潜热通量>感热通量>储热变化．受日照时间的影响,6～10月各分量正值的日持续时间逐渐缩短．月平均结果,白天净辐射6月份最大,10月上旬最小,变化于0～527W·m^-2,夜间的净辐射在0～-121W·m^-2．潜热通量白天和夜间分别在0～441、0～-81W·m^-2,感热通量昼夜分别在0～80、0～-26W·m^-2．储热变化则为0～44、0～-26W·m^-2．白天潜热通量占净辐射的比例8～10月逐渐下降,而感热通量和储热变化的比例9～10月明显上升,特别在严霜后2～3d,出现潜热通量比例突减、感热通量比例突增的现象．文中还对通量观测仪器、方法进行了简要分析．     

A scaling approach for quantifying the net CO2 flux of the Kuparuk River Basin,Alaska

Net CO₂ flux measurements conducted during the summer and winter of 1994–96 were scaled in space and time to provide estimates of net CO₂ exchange during the 1995–96 (9 May 1995–8 May 1996) annual cycle for the Kuparuk River Basin, a 9200 km² watershed located in NE Alaska. Net CO₂ flux was measured using dynamic chambers and eddy covariance in moist‐acidic, nonacidic, wet‐sedge, and shrub tundra, which comprise 95% of the terrestrial landscape of the Kuparuk Basin. CO₂ flux data were used as input to multivariate models that calculated instantaneous and daily rates of gross primary production (GPP) and whole‐ecosystem respiration (R) as a function of meteorology and ecosystem development. Net CO₂ flux was scaled up to the Kuparuk Basin using a geographical information system (GIS) consisting of a vegetation map, digital terrain map, dynamic temperature and radiation fields, and the models of GPP and R. Basin‐wide estimates of net CO₂ exchange for the summer growing season (9 May?5 September 1995) indicate that nonacidic tundra was a net sink of ?31.7 ± 21.3 GgC (1 Gg = 10⁹ g), while shrub tundra lost 32.5 ± 6.3 GgC to the atmosphere (negative values denote net ecosystem CO₂ uptake). Acidic and wet sedge tundra were in balance, and when integrated for the entire Kuparuk River Basin (including aquatic surfaces), whole basin summer net CO₂ exchange was estimated to be in balance (?0.9 ± 50.3 GgC). Autumn to winter (6 September 1995–8 May 1996) estimates of net CO₂ flux indicate that acidic, nonacidic, and shrub tundra landforms were all large sources of CO₂ to the atmosphere (75.5 ± 8.3, 96.4 ± 11.4, and 43.3 ± 4.7 GgC for acidic, nonacidic, and shrub tundra, respectively). CO₂ loss from wet sedge surfaces was not substantially different from zero, but the large losses from the other terrestrial landforms resulted in a whole basin net CO₂ loss of 217.2 ± 24.1 GgC during the 1995–96 cold season. When integrated for the 1995–96 annual cycle, acidic (66.4 + 25.25 GgC), nonacidic (64.7 ± 29.2 GgC), and shrub tundra (75.8 ± 8.4 GgC) were substantial net sources of CO₂ to the atmosphere, while wet sedge tundra was in balance (0.4 + 0.8 GgC). The Kuparuk River Basin as a whole was estimated to be a net CO₂ source of 218.1 ± 60.6 GgC over the 1995–96 annual cycle. Compared to direct measurements of regional net CO₂ flux obtained from aircraft‐based eddy covariance, the scaling procedure provided realistic estimates of CO₂ exchange during the summer growing season. Although winter estimates could not be assessed directly using aircraft measurements of net CO₂ exchange, the estimates reported here are comparable to measured values reported in the literature. Thus, we have high confidence in the summer estimates of net CO₂ exchange and reasonable confidence in the winter net CO₂ flux estimates for terrestrial landforms of the Kuparuk river basin. Although there is larger uncertainty in the aquatic estimates, the small surface area of aquatic surfaces in the Kuparuk river basin (≈ 5%) presumably reduces the potential for this uncertainty to result in large errors in basin‐wide CO₂ flux estimates.