Earth System Model FGOALS-s2: Coupling a dynamic global vegetation and terrestrial carbon model with the physical climate system model

Earth System Models （ESMs） are fundamental tools for understanding climate-carbon feedback. An ESM version of the Flexible Global Ocean-Atmosphere-Land System model （FGOALS） was recently developed within the IPCC AR5 Coupled Model Intercomparison Project Phase 5 （CMIP5） modeling framework, and we describe the development of this model through the coupling of a dynamic global vegetation and terrestrial carbon model with FGOALS-s2. The performance of the coupled model is evaluated as follows. The simulated global total terrestrial gross primary production （GPP） is 124.4 PgC yr-I and net pri- mary production （NPP） is 50.9 PgC yr-1. The entire terrestrial carbon pools contain about 2009.9 PgC, comprising 628.2 PgC and 1381.6 PgC in vegetation and soil pools, respectively. Spatially, in the tropics, the seasonal cycle of NPP and net ecosystem production （NEP） exhibits a dipole mode across the equator due to migration of the monsoon rainbelt, while the seasonal cycle is not so significant in Leaf Area Index （LAI）. In the subtropics, especially in the East Asian monsoon region, the seasonal cycle is obvious due to changes in temperature and precipitation from boreal winter to summer. Vegetation productivity in the northern mid-high latitudes is too low, possibly due to low soil moisture there. On the interannual timescale, the terrestrial ecosystem shows a strong response to ENSO. The model- simulated Nifio3.4 index and total terrestrial NEP are both characterized by a broad spectral peak in the range of 2-7 years. Further analysis indicates their correlation coefficient reaches -0.7 when NEP lags the Nifio3.4 index for about 1-2 months.     

胡杨树轮δ13C记录的艾比湖地区夏季最高温度变化

摘要：艾比湖是新疆北部生态环境最为敏感和脆弱的地区,这里分布的大片长龄胡杨是过去气候变化良好的记录体。本文利用艾比湖东岸的胡杨树轮资料,分析其宽度和稳定碳同位素组成,建立了树轮宽度年表和δ^13C序列,并对δ^13C序列进行了校正处理。树轮参数的气候意义分析表明胡杨树轮宽度所含的气候信息较少,而树轮δ^13C校正序列与精河夏季高温显著负相关,为荒漠平原区树轮气候研究提供了新的资料。研究区夏季的高温超过了光合作用的适宜温度,降低光合作用速率（A）,而地下水埋深较浅,叶片气候导度（g）并没有因受到水分条件限制而减小,在以上两个因素的共同作用下,叶片内部二氧化碳浓度（Ci）升高,导致胡杨δ^13C与夏季高温负相关关系。建立了胡杨树轮δ^13C校正序列与精河夏季高温的转换方程,方差解释量为33．0％。重建的精河145a来夏季高温序列反映了这一地区气候变暖的趋势,其升温的幅度高于北半球夏季升温幅度,但二者冷暖阶段变化并不完全一致。     

格尔木地区总辐射、反射辐射的变化特征

格尔木辐射站是青海省唯一的太阳辐射观测一级站,地处柴达木盆地,太阳总辐射及地表反射辐射均较强.1993—2011年19 a的观测结果表明:反射辐射时总量的变化规律与总辐射时总量同步,只是量值比较小,总辐射瞬时最大值为1 596 W/m²,反射辐射瞬时最大值为383 W/m²;总辐射日总量、反射辐射日总量的年变化曲线呈不规则的正弦波曲线变化过程,两者变化趋势完全一致;总辐射日总量、反射辐射日总量的年变化、年际变化与日照时数相同,说明日照时数是太阳总辐射、反射辐射的重要影响因素之一;总辐射日总量、反射辐射日总量均是夏季>秋季>春季>冬季,反射比是冬季>春季>秋季>夏季;反射比分布主要与太阳高度角的变化有关,反射比的大小取决于地面的性质和状态,地面被积雪覆盖时,各时及日反射比值明显大于晴天和土壤潮湿的时期.     

Rhomboidal versus triangular spherical harmonic truncation: Some verification statistics

Abstract

In the construction of global primitive equation models, based on the spherical harmonic method, two forms of truncation are in general use. Theoretical considerations suggest the triangular truncation method is superior, but the easily coded rhomboidal truncation is more commonly used. A verification experiment employing the Canadian Operational Spectral Model has been performed to determine if the theoretical superiority of the triangular truncation can be realized in practice. It was found that at least in the restricted case of extra‐tropical forecasts of less than 48 h, that the two truncation methods produced forecasts of equivalent accuracy.     

临安大气气溶胶理化特性季节变化

分别利用碳成分分析仪、离子色谱仪和原子吸收光谱仪等获取浙江省临安地区大气气溶胶在春、夏、秋、冬四季的质量浓度、离子与碳成分特性,并对不同粒径气溶胶成分分布特点作了较详细分析。结果表明：气溶胶质量浓度、可溶性离子浓度以及碳成分浓度具有明显的季节变化趋势。整个尺度范围内,气溶胶质量浓度季节变化特点为春季浓度最高,达到534 μg/m3;冬季次之,质量浓度为117.21 μg/m3;夏季浓度最低,平均为65.7 μg/m3;秋季质量浓度98.6 μg/m3。可溶性离子成分在气溶胶中所占比例具有明显的季节性,其中夏季最高为49.4%,春季最低为11.3%。硫酸根离子SO42-和氨根离子NH4+和硝酸根离子NO3- 3种离子浓度之和约占离子总量的75%~83%。受温度影响,硝酸根离子NO3-浓度随季节变化幅度较大,夏季平均浓度为1.7 μg/m3, 冬季平均浓度为11.5 μg/m3,是夏季浓度的6.8倍。碳浓度分布特点显示,气溶胶中元素碳浓度春季最高,夏季最低。有机碳浓度春季最高,冬季最低。气溶胶粒度分布特点也非常明显。四季中粒径小于11 μm（PM11）的气溶胶均占气溶胶总量的90%以上,粒径小于2.1 μm（PM2.1）的气溶胶占到气溶胶总量的53%以上。可溶性离子在粒径小于2.1 μm气溶胶颗粒中,以硫酸根离子、氨根离子和硝酸根离子为主。碳成分尺度分布特征为颗粒越小,有机碳及元素碳浓度越高。     

盘锦芦苇湿地土壤微生物特征分析

基于盘锦湿地生态系统野外观测站芦苇群落生长季6～9月的定位观测资料,分析了芦苇湿地土壤微生物季节动态及其与环境因子的关系。结果表明:盘锦芦苇湿地的土壤细菌、放线菌、真菌以及微生物的总数在生长季节呈现出先减少、后增加的变化趋势。湿地的土壤细菌、放线菌以及微生物的总数在8月达到最小,而真菌数量在7月达到最小。湿地土壤中,细菌数量最大,其次是放线菌,最少的是真菌。对细菌、放线菌、真菌以及微生物总数与环境因子的相关分析表明,细菌、放线菌与微生物总数主要受水分影响,而真菌则受水分与气温的协同作用影响     

大气臭氧总量的经验计算方法

依据臭氧生消与紫外辐射(UV)能量利用相互作用的观点,考虑与臭氧有关的主要因子UV、大气中物质在化学和光化学反应中对UV能量的吸收、气溶胶粒子的散射等,在分析1990—1992年臭氧总量、太阳辐射、气象资料的基础上,建立了计算臭氧总量的经验模式,其优点是所用资料均可由常规气象站获得。结果表明,计算值与观测值符合得比较好。利用该经验模式计算了北京地区1979年1月—1996年6月的臭氧总量,计算值与观测值同样比较一致,二者相对偏差的最大值、最小值、平均值分别为15.2%、0.05%和4.9%,相对偏差在±10%之内的比例为91.4%,因而该经验模式是合理、可行的。1991年之后北京地区臭氧的下降与Pinatubo火山气溶胶的影响有关。     

Evaluating the Tree Population Density and Its Impacts in CLM-DGVM

Vegetation population dynamics play an essential role in shaping the structure and function of terrestrial ecosystems.However,large uncertainties remain in the parameterizations of population dynamics in current Dynamic Global Vegetation Models(DGVMs).In this study,the global distribution and probability density functions of tree population densities in the revised Community Land Model-Dynamic Global Vegetation Model(CLM-DGVM) were evaluated,and the impacts of population densities on ecosystem characteristics were investigated.The results showed that the model predicted unrealistically high population density with small individual size of tree PFTs(Plant Functional Types) in boreal forests,as well as peripheral areas of tropical and temperate forests.Such biases then led to the underestimation of forest carbon storage and incorrect carbon allocation among plant leaves,stems and root pools,and hence predicted shorter time scales for the building/recovering of mature forests.These results imply that further improvements in the parameterizations of population dynamics in the model are needed in order for the model to correctly represent the response of ecosystems to climate change.     

CHARACTERISTICS OF UT/LS CARBON MONOXIDE INTRASEASONAL OSCILLATIONS AND THEIR IMPACT FACTORS OVER THE TIBETAN PLATEAU AND ITS ADJACENT AREAS IN SUMMER

The study presented herein investigated the main characteristics of carbon monoxideintraseasonal variability and evaluated its possible impact factors using the upper troposphere and lowerstratosphere (UT/LS) Aura Microwave Limb Sounder (MLS) observations over Tibetan Plateau and itsadjacent areas in summer (June to August) of 2005 and 2006. Observations show a persistent constituentextreme extending up into the UT/LS throughout summer, as well as a temporally reversed phase variationbetween the carbon monoxide and ozone in UT/LS. The intraseasonal oscillations (ISOs) of carbonmonoxide during summer are investigated by using methods of wavelet and band pass filter analysis. It isfound that ISOs over the Tibetan Plateau have periods of 10 to 20 days and 30 to 60 days. The formermainly appeared in upper troposphere while the latter in lower stratosphere. Further analysis shows thatthese two periods of ISOs in UT/LS are mainly in phase to the activities of convection over the south of theplateau and the variation of South Asia High, respectively. The above two factors and their dynamicalcoupling may be responsible for the tracer ISOs at different levels.     

中国土壤有机碳库及其演变与应对气候变化

 通过综述和评价中国土壤,特别是农田土壤有机碳库（以下简称碳库）的现状与演变态势, 讨论其对我国应对气候变化的意义, 提出了我国土壤碳库及其演变与应对气候变化的基本国情是：1) 我国土壤背景碳储量较低且区域分布不均衡;2) 我国土壤固碳效应明显,未来固碳减排潜力显著;3) 技术和政策是实现和提高我国土壤碳汇、促进我国应对气候变化能力建设的重要途径。建议进一步加强对我国农田土壤固碳减排的研发投入, 完善农业应对气候变化的相关政策和鼓励措施体系,研究构建气候友好的新型农业,以期在提高和稳定农业生产力与应对气候变化能力上获得双赢。