Evaluating Common Land Model Energy Fluxes Using FLUXNET Data

Given the crucial role of land surface processes in global and regional climates, there is a pressing need to test and verify the performance of land surface models via comparisons to observations. In this study, the eddy covariance measurements from 20 FLUXNET sites spanning more than 100 site-years were utilized to evaluate the performance of the Common Land Model （CoLM） over different vegetation types in various climate zones. A decomposition method was employed to separate both the observed and simulated energy fluxes, i.e., the sensible heat flux, latent heat flux, net radiation, and ground heat flux, at three timescales ranging from stepwise （30 rain） to monthly. A comparison between the simulations and observations indicated that CoLM produced satisfactory simulations of all four energy fluxes, although the different indexes did not exhibit consistent results among the different fluxes, A strong agreement between the simulations and observations was found for the seasonal cycles at the 20 sites, whereas CoLM underestimated the latent heat flux at the sites with distinct dry and wet seasons, which might be associated with its weakness in simulating soil water during the dry season. CoLM cannot explicitly simulate the midday depression of leaf gas exchange, which may explain why CoLM also has a maximum diurnal bias at noon in the summer. Of the eight selected vegetation types analyzed, CoLM performs best for evergreen broadleaf forests and worst for croplands and wetlands.

Land Response to Atmosphere at Different Resolutions in the Common Land Model over East Asia

Towards a better understanding of hydrological interactions between the land surface and atmosphere, land surface mod- els are routinely used to simulate hydro-meteorological fluxes. However, there is a lack of observations available for model forcing, to estimate the hydro-meteorological fluxes in East Asia. In this study, Common Land Model （CLM） was used in offline-mode during the summer monsoon period of 2006 in East Asia, with different forcings from Asiaflux, Korea Land Data Assimilation System （KLDAS）, and Global Land Data Assimilation System （GLDAS）, at point and regional scales, separately. The CLM results were compared with observations from Asiaflux sites. The estimated net radiation showed good agreement, with r = 0.99 for the point scale and 0.85 for the regional scale. The estimated sensible and latent heat fluxes using Asiaflux and KLDAS data indicated reasonable agreement, with r = 0.70. The estimated soil moisture and soil temperature showed similar patterns to observations, although the estimated water fluxes using KLDAS showed larger discrepancies than those of Asiaflux because of scale mismatch. The spatial distribution of hydro-meteorological fluxes according to KLDAS for East Asia were compared to the CLM results with GLDAS, and the GLDAS provided online. The spatial distributions of CLM with KLDAS were analogous to CLM with GLDAS, and the standalone GLDAS data. The results indicate that KLDAS is a good potential source of high spatial resolution forcing data. Therefore, the KLDAS is a promising alternative product, capable of compensating for the lack of observations and low resolution grid data for East Asia.

Coupling the Common Land Model to ECHAM5 Atmospheric General Circulation Model

The ECHAM5 model is coupled with the widely used Common Land Model(CoLM). ECHAM5 is a state-of-theart atmospheric general circulation model incorporated into the integrated weather and climate model of the Chinese Academy of Meteorological Sciences(CAMS-CSM). Land surface schemes in ECHAM5 are simple and do not provide an adequate representation of the vegetation canopy and snow/frozen soil processes. Two AMIP(Atmospheric Model Intercomparison Project)-type experiments using ECHAM5 and ECHAM5-CoLM are run over 30 yr and the results are compared with reanalysis and observational data. It is found that the pattern of land surface temperature simulated by ECHAM5-CoLM is significantly improved relative to ECHAM5. Specifically, the cold bias over Eurasia is removed and the root-mean-square error is reduced in most regions. The seasonal variation in the zonal mean land surface temperature and the in situ soil temperature at 20-and 80-cm depths are both better simulated by ECHAM5-CoLM. ECHAM5-CoLM produces a more reasonable spatial pattern in the soil moisture content, whereas ECHAM5 predicts much drier soils. The seasonal cycle of soil moisture content from ECHAM5-CoLM is a better match to the observational data in six specific regions. ECHAM5-CoLM reproduces the observed spatial patterns of both sensible and latent heat fluxes. The strong positive bias in precipitation over land is reduced in ECHAM5-CoLM, especially over the southern Tibetan Plateau and middle–lower reaches of the Yangtze River during the summer monsoon rainy season.

An Empirical Investigation of Common Sense of Land Use from a Statistical Approach

Recently, ontological study has been one of the key concerns of geographic information science, a number of studies have been conducted in both of philosophical and knowledge engineering approach. Some studies pointed out the importance of human cognition and social context for development of ontologies. This paper presents empirical investigation of common sense of land use categories for development of suitable ontologies for each cultural or speech communities. Distinctions and characteristics in perceiving land use categories were described by a psychological method that was submitted to Japanese graduate and undergraduate students. In addition the results were analyzed using corresponddence analysis, a statistical technique for categorical data. This analysis serves to clarify the dominant determining factors for land use categories.

从“氏族之人”到“编户齐民”——试论先秦时期社会成员身份的变迁

夏商西周时期,社会上几乎所有的人都生活于“族”之中。这些族,夏商时期称为“氏族”,西周时期则多称为“宗族”。春秋战国时期,虽然“人”“民”多混用无别,但两者的使用却出现了有所侧重的情况。“民”能够以地域为称,但并不以族为称,它所表现的是社会成员的地域特征,而“人”则可以表现其作为某族的血缘关系特征。社会成员间血缘关系的影响在削弱,而国家地域关系的影响在增强。社会成员身份的巨大变化是由氏族(宗族)之人,变成了国家控制下的编户齐民。“编户齐民”肇端于战国时期诸国授田制度的实施,到秦代则成为国家控制天下民众的最主要的制度。这种居民身份的变化深刻地影响着古代中国的历史发展。

Improving the CoLM in Taklimakan Desert Hinterland with Accurate Key Parameters and an Appropriate Parameterization Scheme

Improving and validating land surface models based on integrated observations in deserts is one of the challenges in land modeling. Particularly, key parameters and parameterization schemes in desert regions need to be evaluated in-situ to improve the models. In this study, we calibrated the land-surface key parameters and evaluated several formulations or schemes for thermal roughness length （z 0h ） in the common land model （CoLM）. Our parameter calibration and scheme evaluation were based on the observed data during a torrid summer （29 July to 11 September 2009） over the Taklimakan Desert hinterland. First, the importance of the key parameters in the experiment was evaluated based on their physics principles and the significance of these key parameters were further validated using sensitivity test. Second, difference schemes （or physics-based formulas） of z 0h were adopted to simulate the variations of energy-related variables （e.g., sensible heat flux and surface skin temperature） and the simulated variations were then compared with the observed data. Third, the z 0h scheme that performed best （i.e., Y07） was then selected to replace the defaulted one （i.e., Z98）; the revised scheme and the superiority of Y07 over Z98 was further demonstrated by comparing the simulated results with the observed data. Admittedly, the revised model did a relatively poor job of simulating the diurnal variations of surface soil heat flux, and nighttime soil temperature was also underestimated, calling for further improvement of the model for desert regions.

中国式现代化征程中再兴土地财政能实现共同富裕吗

共同富裕是社会主义的本质要求,而要实现共同富裕伟大目标必须缩小城乡居民收入差距。基于2004—2019年285个地级城市面板数据,运用SGMM模型,对地级城市在中国式现代化征程中继续推行土地财政模式能否实现城乡居民共同富裕的问题进行探索。结果显示:土地财政对城乡居民收入差距的影响呈现出“倒U型”路径,而对城市内部居民收入差距的影响为“正U型”,表明再推行土地财政模式可能继续拉大城市居民收入差距;土地财政拉大了农村居民收入差距,地级城市土地出让金额占城市预算收入的比重每提高1%,农村居民收入差距可能增加1.3%。机制检验结果显示,土地财政通过地级城市经济总量的快速扩张拉大居民收入差距。建议地级城市通过控制土地财政规模以防止城乡居民收入差距的再扩大,并逐步探索创新与改革土地财政模式,加快完善中国式经济发展中的利益分配与共享机制,有序实现城乡居民共同富裕。

共同富裕愿景下农村土地捐赠问题研究

遵循第三次分配和共同富裕的理念与精神,创新地提出农村土地捐赠的概念。基于科学合理的激励机制,促使部分先富裕起来的农户将土地捐赠给本集体经济组织内低收入的无地少地农户,以达到先富带后富、促进共同富裕的目标。从此视角出发,构建起农村土地捐赠的运行机制,在农村土地捐赠执行过程中可能面临着三个方面的问题:土地捐赠的参与主体不积极和捐赠数量不充分、土地捐赠的管理主体和监督主体不明确、捐赠土地的再利用方式不清晰。这些问题的形成原因主要包括:农村土地捐赠的法律政策不健全不完善、农村土地捐赠实施机构的选择面临着自治和法治的困局、农村土地捐赠激励机制的严重缺位、农村土地捐赠的社会氛围尚未形成。据此,提出四条对策建议以助力农村土地捐赠的实现:建立并完善农村土地捐赠的法律政策体系、组建高效联动的农村土地捐赠执行机构、构建多层次的农村土地捐赠激励机制、倡导先富带后富的农村土地捐赠社会氛围。

共同富裕视域下农村宅基地增值收益分配法律制度——以土地发展权共享论为分析框架

分配制度是促进共同富裕的基础,宅基地增值收益分配制度是判断宅基地制度改革质量的重要依据。土地征收制度的局限性和宅基地收益权能的显化,使得我们开始重新反思“土地发展权私有论”与“土地发展权国有论”的法律正当性。基于社会主义公有制的所有制形式,国家必然享有土地发展权并参与分配;社会主义市场经济体制,也为土地所有权人及用益物权人的土地发展权奠定了充分的法律基础,从而形成“土地发展权共享论”。构建宅基地增值收益分配制度,需要结合中国国情,以“初次分配、再分配、第三次分配协调配套”为基本原则。在初次分配中,以产权为分配基础,促进土地发展权人机会平等,探索土地要素收入;在二次分配中,以现有税收法律体系为基础,规范收入分配秩序、调节过高收入;在三次分配中,确定“无偿原始取得宅基地使用权”的特殊情形,实现农民集体对集体成员的自愿性、自治性、公益性救助帮扶。三环节环环相扣、三层次层层递进,扎实推进共同富裕。

大国的城乡融合:城市化和相关改革的进展与问题

在中国这样一个大国,城乡融合不应局限于市域范围之内,而应着眼于全国范围内跨地区的城乡间分工协作。当前,全国范围内已经出现了人口流入和流出两类地区的分化,存量建设用地(包括农村集体经营性用地和宅基地)与人口流动的空间布局日益呈现出巨大的错配。为了推动全国范围内的城乡融合发展,必须加快构建全国统一的劳动力和土地市场。随着户籍制度的改革加快推进,未来的改革重点将是土地市场。根据农村土地制度的改革试点经验,在维护农民权益的原则下,由中央政府提供制度保障与政策支持,地方政府根据试点经验和当地实际情况进行改革探索,助力共同富裕的目标。

空间整合与乡村振兴:新时代推进农民集中居住的实践逻辑

推动农民集中居住,建设新型农村社区是落实乡村振兴战略,加快推进农业农村现代化的重要政策工具。但不可否认的是,这一政策自实施以来就备受争议。通过与新马克思主义空间生产理论的对话和对农民集中居住实践经验的再反思,本文提出基于空间整合的三维分析框架,即通过治理性发展、社区性整合和生活性重建的协调发展,实现乡村空间再生产,在城乡协调发展背景下加快推进农业农村现代化。这为解决当前农民集中居住社区的治理困境提供了综合性思路,也为推动新时代农民集中居住,解决城乡发展不平衡、不充分问题,落实乡村振兴战略提供理论支撑。

共建共治共享理念视角下农地旅游化利用中农民利益保护研究

利益主体共享成果是农地旅游化利用的目的,但现实中农民利益受损说明这一目的并未实现,不完善的共建共治机制是其主要原因。因此,保护农民利益,一方面需要健全农民参与机制,为农民共享农地旅游化利用成果提供基础;另一方面应该赋予农民平等的参与决策权,为农民共享农地旅游化利用成果提供保障。

共同富裕视域下的土地资源资产收益问题研究

土地资源资产收益及其管理是实现共同富裕过程中必须研究和解决的重大问题。文章基于我国土地产权及收益分配理论,分析了土地财富规模及收益分配结构,阐述了国有土地出让市场存在的土地流拍、国企接盘、总体亏损、债务攀升等问题。基于“国有资产+国有资源+国有银行”这一社会主义经济制度特征,以促进共同富裕为导向,统筹考虑收益分配、住房保障、地方债务问题,综合采取财政、金融、法律、信息化等政策工具,从全面推行住房双轨保障、逐步完善土地出让制度、持续提高公共治理能力等三方面提出完善土地资源资产收益制度体系的建议。

基于共同富裕逻辑的土地制度改革研究

基于共同富裕逻辑,对土地制度改革的必要性和艰巨性进行分析,全面深化土地制度改革要以土地善治推进“地权平等、地尽其用、地利共享”,促进“土地要素配置市场化、进城农民市民化、社会流动自由化”,提出了坚持以人定地促进土地要素自由流动和优化配置、推进农村集体经营性建设用地入市和激活宅基地的财产属性、实行农村土地承包权股份制改革、探索建立基于土地发展权的耕地保护和生态保护补偿制度、改革土地利用管理方式和完善以地谋发展机制等改革举措建议。

共同富裕背景下农户土地承包权退出意愿影响路径研究——基于不同年龄阶段的群组比较

本文基于2022年810份农户微观调研数据,运用结构方程模型探讨农户土地承包权退出意愿影响路径,并对比分析不同年龄阶段农户影响路径差异。研究结果表明:(1)农户土地承包权退出意愿受家庭特征、土地特征、认知特征及承包权退出补偿条件特征影响,其中承包权退出补偿条件特征影响效应最强。(2)土地特征和认知特征以直接和间接两种方式对农户土地承包权退出意愿产生影响。(3)不同年龄阶段农户土地承包权退出意愿影响因素有所差异,影响路径也略有不同。因此,应依据农户特征探索分类型、分阶段、多样化的土地承包权退出路径,针对不同年龄阶段的农户实施差别化退出激励政策及补偿政策,完善农村社会保障体系,公开土地承包权退出补偿信息与制度。

燕麦箭筈豌豆间作及施肥对科尔沁沙地饲草产量和品质的影响

于2020-2021年在中国科学院西北奈曼沙漠化研究站,以饲用燕麦和箭筈豌豆为研究对象,在燕麦灌浆期刈割后进行饲草复播,采用双因素随机区组设计,设置3种种植模式,即燕麦单作(SO)、箭筈豌豆单作(SV)和燕麦箭筈豌豆间作(IOV);4种施肥模式,即不施肥(N)、单施化肥(C)、单施生物有机肥(M)和有机肥与无机肥配施(G),通过测定饲草产量和营养品质,分析种间竞争相关指标,以明确间作与施肥对复种燕麦、箭筈豌豆饲草产量和营养品质的影响。结果表明:间作和施肥提高了燕麦和箭筈豌豆的地上部生物量,在G处理下,间作燕麦(IO)和间作箭筈豌豆(IV)的干草产量较相应单作处理分别提高了4.34%、1.79%和27.63%、34.12%。间作处理的土地当量比大于1,表明燕麦箭筈豌豆间作具有土地利用优势;通过种间竞争指标分析发现,箭筈豌豆产量的提高对于发挥间作优势具有重要的作用。IO-G处理的粗蛋白和粗脂肪含量较同水平下单作处理分别提高了24.81%、36.60%和20.21%、6.15%,IV-G处理的可溶性糖含量较IV-N处理提高18.55%和34.36%;IO-G处理下的中性洗涤纤维和酸性洗涤纤维含量较同水平下单作燕麦平均降低6.47%和12.10%,间作燕麦和间作箭筈豌豆的相对饲用价值在G处理下较N处理分别提高39.18%、58.81%和25.68%、55.46%。间作种植模式还提高了饲草潜在干物质采食量、消化性干物质及代谢能含量,使饲草营养品质从能量积累到适口性都有所提升。综上可知,燕麦箭筈豌豆间作结合有机肥和无机肥配施可以改善内蒙古东部沙质土壤地区饲草的营养品质,提高饲草产量。

征地价格扭曲对共同富裕的影响

实现全体人民共同富裕是中国式现代化的本质要求,但当前我国发展不平衡不充分的问题仍然突出,城乡区域发展和收入分配差距仍然较大。利用手动收集的各省平均征地补偿标准,基于征地补偿标准与平均土地出让价格之比衡量各省征地价格扭曲程度,考察征地价格扭曲对我国共同富裕的影响,发现:我国多省征地补偿标准调整慢,这也是造成征地价格扭曲的主要原因;征地价格扭曲会拉大城乡收入比,征地价格扭曲每降低1%,会使得城乡收入比降低0.616%;征地价格扭曲会恶化城镇收入分配结构,不利于扩大中等收入群体。建立合理的征地补偿机制,推进农村集体经营性建设用地入市、提高农民土地增值收益分享比例,调整财政政策方向、相时而动增加廉租房、公租房和保障性住房供给,加强农民土地权益的政策宣传和法律保障,有助于乡村振兴的有效实施,促推共同富裕的实质性进展。

“负债式”融资如何影响劳动力再配置?——基于土地金融发展视角

劳动力作为社会性流动的主体,其合理有序的流动和配置有利于改善资源配置效率,提高中等收入群体比重,推进共同富裕。然而我国当前存在劳动力再配置不合理现象,为探究该现象背后的原因与理论机制,本文从理论和实证两个方面对此进行分析。研究发现,土地金融的发展致使不同行业的劳动力转移状态存在差异,是导致劳动力再配置不合理的重要原因。投资“双重性”的中介效应、产业结构的调节效应是土地金融促进劳动力跨行业转移的重要渠道。土地金融对劳动力再配置的影响在经济发展水平较高、人口密度较大以及对土地财政依赖程度较大的城市更加显著。

统分结合下土地集约高效利用的创新实践--以宁夏西吉县“三统三分”为例

依靠土地促进农民持续增收推动共同富裕是实现农业现代化的重要举措。文章首先阐述了统分结合经营体制下我国土地集约高效利用的经典实例,从理论层面对其进行了分析,并将新型做法与传统做法进行了对比评述;然后以宁夏西吉县“三统三分”的做法和取得的成效为例,总结了这一创新做法在乡村振兴背景下对促进城乡协同发展、推进共同富裕的有益启示,并对该模式的复制推广提出了若干建议。

社会资本视角下农地利用的“反公地悲剧”对策研究

农地的高效利用有利于保障粮食安全,促进农业的可持续发展,扎实推进乡村振兴。以强化和保护农民土地产权为重要特征的农地确权有利于形成产权清晰、权能明确、权益保障、分配合理的农村集体土地产权制度,但也使得农地产权变得更加细碎化,从而可能导致农地利用存在“反公地悲剧”风险。社会资本可以通过信任机制、声誉机制以及规范机制有效降低这种风险。因此,需要通过弘扬民族优秀传统文化,加强思想道德建设,健全和完善村民自治制度,以及发展农村非农经济等途径丰富农村社会资本,从而降低农地利用“反公地悲剧”风险,使农地确权的积极效应得到更大程度的发挥,为乡村振兴战略的实施提供有力支持。