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Climatic drivers for canopy leaf shedding and flush of evergreen broadleaved forest biome are still unclear at the continental scale across tropical and subtropical region. This imposes a challenge for modeling pantropical photosynthesis seasonality in Earth system models. Here, we examined three potential climatic triggers, vapor pressure deficit–a proxy of atmospheric water deficit, downward shortwave incoming solar radiation–a proxy of sunlight availability, and terrestrial water storage–a proxy of soil water availability observed by the Gravity Recovery and Climate Experiment, by comparing with two satellite phenological proxies–the Enhanced Vegetation Index and Continuous Solar‐induced chlorophyll fluorescence. Results show that tropical leaf phenology varies greatly from equatorial bimodal seasonality to higher‐latitude unimodal seasonality. Sunlight availability dominantly controls the whole seasonal leaf phenology across the pantropical region. Atmospheric dryness is one main type of water stress for leaf phenology during the first half year. However, soil water stress strongly inhibits the first‐half of leaf phenology in tropical Asia and the second‐half of leaf phenology in Congo, but shows rare constraint on the leaf phenology in Amazon. Ignoring these various roles of soil moisture availability and atmospheric dryness in influencing tropical leaf phenology might lead to unexpected uncertainty for predicting the water and carbon cycles of tropical forest ecosystem in Earth system models.

International audience; Amazonian evergreen forests show distinct canopy phenology and photosynthetic seasonality but the climatic triggers are not well understood. This imposes a challenge for modeling leaf phenology and photosynthesis seasonality in land surface models (LSMs) across Amazonian evergreen forest biome. On continental scale, we tested two climatic triggers suggested by site observations, vapor pressure deficit (VPD), and short-wave incoming radiation (SW) for defining leaf shedding and incorporated VPD- and SW-triggered new canopy phenology modules in the ORCHIDEE LSM (hereafter VPD-AP and SW-AP versions). Our results show that both VPD and SW are plausible precursors of large scale litterfall seasonality across the basin by comparing against in situ data from 14 sites. Specially, both VPD-AP and SW-AP correctly capture the increases in litterfall during the early dry season, followed by a flush of new leaves with increasing photosynthetic rates during the later dry season. The VPD-AP version performs better than the SW-AP version in capturing a dry-season increase of photosynthesis across the wet Amazonia areas where mean annual precipitation exceeds 2,000 mm yr$^{-1}$, consistent with previous satellite data analysis. Both VPD-AP and SW-AP model versions perform well in northern, central and southern Amazon regions where the SW seasonality is unimodal, but miss the seasonality of satellite GPP proxies in the eastern region off the coast of Guyana shield where SW seasonality is bimodal. Our findings imply that atmospheric dryness and sunlight availability likely explain the seasonality of leaf shedding and leaf flush processes, respectively, and consequently control canopy photosynthesis in Amazonian evergreen forests

The aims of the present study were to determine the pH variation and chemical feature of atmospheric precipitation during the research period. We also investigated the redistribution characteristics of rainfall while passing through the canopy layer, leaf-litter layer and soil layer, successively to quantify the acid rain buffering capacity of these spatial levels in the evergreen broadleaved forest (EBF), deciduous broadleaved forest (DBF) and coniferous forest (CF) in Guangzhou urban area, China. Results showed that the rainfall was typically acidic, and the acid rain type in Guangzhou urban area is converted from sulfuric acid type to mixed type of sulfuric acid and nitric acid. The major ions from the canopy to the forest floor differed within the three forest types. However, the enrichment phenomenon of base cations in soil leachate in EBF and DBF implied that nutrient loss was more serious in the broadleaved forest than in the coniferous forest. Variability of ionic concentration and pH in the vertical sequence of different tree species showed that the net ion concentration variation index has a significant conic relationship with ne pH change rate. We also built an acid rain buffering index, which combines the neutralization and interception effects of vegetation to acid rainfall. The present results indicated that the three forest types in urban Guangzhou all have certain buffering capacity to acid rain, and following the order: DBF > EBF > CF. In the meanwhile, the forest canopy is the biggest acid rain buffer in urban Guangzhou, following by the soil.

© 2016 IEEE. 3D object reconstructions obtained from 2D or 3D cameras are typically noisy. Probabilistic algorithms are suitable for information fusion and can deal with noise robustly. Consequently, these algorithms can be useful for accurate surface reconstruction. This paper presents an approach to estimate a probabilistic representation of the implicit surface of 3D objects. One of the contributions of the paper is the pipeline for generating an accurate reconstruction, given a set of sparse points that are close to the surface and a dense noisy point cloud. A novel submapping method following the topology of the object is proposed to generate conditional independent Gaussian Process Implicit Surfaces. This allows inference and fusion mechanisms to be performed in parallel followed by information propagation through the submaps. Large datasets can efficiently be processed by the proposed pipeline producing not only a surface but also the uncertainty information of the reconstruction. We evaluate the performance of our algorithm using simulated and real datasets.

International audience; Leaf phenology in the humid tropics largely regulates the seasonality of forest carbon and water exchange. However, it is inadequately represented in most global land surface models due to limited understanding of its controls. Based on intensive field studies at four Amazonian evergreen forests, we propose a novel, quantitative representation of tropical forest leaf phenology, which links multiple environmental variables with the seasonality of new leaf production and old leaf litterfall. The new phenology simulates higher rates of leaf turnover (new leaves replacing old leaves) in dry seasons with more sunlight, which is then implemented in ORCHIDEE, together with recent findings of ontogeny-associated photosynthetic capacity, and is evaluated against ground-based measurements of leaf phenology (canopy leaf area index and litterfall), eddy covariance fluxes (photosynthesis and latent heat), and carbon allocations from field observations. Results show the periodical cycles of solar radiation and vapor pressure deficit are the two most important environmental variables that are empirically related to new leaf production and old leaf abscission in tropical evergreen forests. The model with new representation of leaf phenology captures the seasonality of canopy photosynthesis at three out of four sites, as well as the seasonality of litterfall, latent heat, and light use efficiency of photosynthesis at all tested sites, and improves the seasonality of carbon allocations to leaves, roots, and sapwoods. This study advances understanding of the environmental controls on tropical leaf phenology and offers an improved modeling tool for gridded simulations of interannual CO2 and water fluxes in the tropics.

Lightweight, low-cost, and effective microwave-absorbing materials are important in electronics, communication, and military defense. Recently, microwave-absorbing materials stemming from biomass have drawn increasing attention for their sustainable properties, low cost, and high performances. In this work, loofah-sponge-derived carbon/CoFe2O4 composites have been prepared by functionalization and subsequent pyrolysis treatment. The porous composites prepared from the loofah sponge exhibit a typical lotus-root-like structure with low density. The composites exhibit an efficient absorption value of −43.8 dB at 8.3 GHz (X band) with a thickness of 3 mm. The high-performance absorption is ascribed to the synergistic attenuation effect of magnetic nanoparticles and dielectric lotus-root-like carbon substrate. The obtained results demonstrated that the loofah-sponge-derived carbon/CoFe2O4 composites with lotus-root-like microstructure have great potential to be lightweight and low-cost microwave-absorbing mate...

In general, the in-vehicle speech enhancement is an application of the microphone array speech enhancement in particular acoustic environments. However, in this paper, we introduce a novel in-vehicle speech enhancement method based on distributed-microphones. The distributed-microphone signals have some features that the signals captured by microphone array do not have. Although distributed-microphones are not frequently used for speech enhancement, they can solve some practical problems, which cannot be solved by microphone array. In this paper, we propose a novel method using the signals acquired by distributed-microphones to enhance the speech corrupted by noise in-vehicle. The final enhanced speech is generated mainly by two steps. We first obtain the primary enhanced speech in each channel via sparse and low-rank spectrogram decomposition. Then based on the average improvements of segSNR (signal-to-noise ratio) and PESQ (perceptual evaluation of speech quality) in each channel, we fuse the primary enhanced speech in all channels into a single channel enhanced speech. In terms of PESQ and segSNR of the final enhanced speech, our approach outperforms several traditional approaches.

Two lanthanide–organic frameworks [Ln(HPIDC)(m-bdc)·1.5H2O]n (Ln = Eu 1 or Tb 2; H3PIDC = 2-(4-pyridyl)-1H-imidazole-4,5-dicarboxylic acid; m-H2bdc = 1,3-benzenedicarboxylic acid) were synthesized under hydrothermal conditions. Compounds 1 and 2 are all of a 3D 6-connected pcu topology. There are uncoordinated nitrogen atoms in the molecule, indicating that the uncoordinated pyridine groups and imidazole groups can serve as functional groups. We tested their luminescence detection ability for cations and anions. Fluorescence measurements show that two compounds (1 and 2) can detect Cr2+ ions and Cr2O72− anions with high selectivity and sensitivity, which suggests that the two Ln-MOFs are promising functional luminescent sensor materials for sensing metal ions and anions.

Global studies have observed divergent impacts of forest cover changes on water yields and biophysical effects on local temperatures. These two topics have long been debated by the scientific community. Here, we built a quantitative link between the negative/positive effects of forest cover changes on water yields and the biophysical cooling/warming effects of forest cover on local temperatures. This model performs well across 12 paired watersheds and eddy covariance observations worldwide. Our results show that the directions of forest biophysical effects on temperatures are strongly related to the directions of water yield effects caused by the forest cover changes. In general, the water yield effects associated with forest biophysical processes increase significantly as climatic dryness increases; and these parts are usually larger than those from the background climate. Notably, the ratio of water yield differences to corresponding temperature changes caused by forest cover changes is larger in a dry climate than that in a humid climate. Our findings support the hypothesis that forest water yield in the dry climate regions is more sensitive to land cover changes than that in the humid climate regions. This study provides new insights into explaining the differences in water yield effects of forest cover changes between the dry and humid climates.

In this study, lightweight but stiff carbon monolith with unique laminated inner structure for high electromagnetic interference (EMI) shielding is designed and prepared. The carbon monolith is consisting of carbon honeycomb structure which was filled with a horizontal laminated reduced graphene foam structure that is perpendicular to the cell wall. The stiff carbon honeycomb (CH) structure not only acts as a conductive and load-bearing framework, but also as the induced source for the growth of ice crystals to make a highly aligned laminated structure in the reduced graphene oxide (rGO) foam, by utilizing the big difference in thermal conductivity between air and the carbon cell wall. Consequently, a EMI shielding effectiveness of around 36–43 dB and remarkable specific EMI shielding effectiveness of 688.5 dB cm 3 g −1 in the X-band is achieved. More importantly, the addition of CH structure significantly increases the compressive stress of rGO foam to 2.02 MPa, almost which is 6760 times higher than common rGO foam. Moreover, the carbon monolith shows a thermal conductivity of 0.057 W/(m·K) and exhibits good flame retardancy. These results indicate that the carbon monolith is an ideal component for high-performance EMI shielding material, which has great potential applications in aviation and the aerospace industry.

Electrochemical synthesis has been proved to be a versatile and simple approach for the preparation of nanoparticles. In this work, an electrochemical method was successfully applied to synthesize selenium nanoparticles (SeNPs) via using selenium powder doped carbon paste electrode. SeNPs were spherical with diameters of about 85, 43 and 60 nm and well dispersed in the presence of sucrose, polyvinylpyrrolidone and sodium dodecyl sulfonate (SDS), respectively. Surprisingly, when adding cetane trimethyl ammonium bromide (CTAB) into the spherical SeNPs modified with SDS, spherical SeNPs changed to sea urchin-like SeNPs by electrostatic assembly. The effects of SDS and CTAB on the morphology of SeNPs were investigated.

International audience; Despite its perennial canopy, the Amazonian tropical evergreen forest shows significant canopy growth seasonality, which has been represented by optical satellite-based observations. In this paper, a new Microwave Temperature–Vegetation Drought Index (MTVDI) based on Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) sensors was used to capture the canopy seasonality from 2003 to 2010 in comparison with four climatic dryness indicators (Palmer Drought Severity Index (PDSI), Climatological Water Deficit (CWD), Terrestrial Water Storage (TWS), Vapor Pressure Deficit (VPD)) and two photosynthesis proxies (Enhanced Vegetation Index (EVI) and Solar-Induced chlorophyll Fluorescence (SIF)), respectively. Our results suggest that the MTVDI shows opposite seasonal variability with two photosynthesis proxies and performs better than the four climatic dryness indicators in reflecting the canopy photosynthesis seasonality of tropical forests in the Amazon. Besides, the MTVDI captures wet regions that show green-up during the dry season with mean annual precipitation higher than 2000 mm per year. The MTVDI provides a new way for monitoring the canopy seasonality of tropical forests from microwave signals.

Digitizing the land surface temperature (Ts) and surface soil moisture (mv) is essential for developing the intelligent Digital Earth. Here, we developed a two parameter physical-based passive microwave remote sensing model for jointly retrieving Ts and mv using the dual-polarized Tb of Aqua satellite advanced microwave scanning radiometer (AMSR-E) C-band (6.9 GHz) based on the simplified radiative transfer equation. Validation using in situ Ts and mv in southern China showed the average root mean square errors (RMSE) of Ts and mv retrievals reach 2.42 K (R2 = 0.61, n = 351) and 0.025 g cm−3 (R2 = 0.68, n = 663), respectively. The results were also validated using global in situ Ts (n = 2362) and mv (n = 1657) of International Soil Moisture Network. The corresponding RMSE are 3.44 k (R2 = 0.86) and 0.039 g cm−3 (R2 = 0.83), respectively. The monthly variations of model-derived Ts and mv are highly consistent with those of the Moderate Resolution Imaging Spectroradiometer Ts (R2 = 0.57; RMSE = 2.91...

Two three-dimensional (3-D) MOFs, [(C2H5)4N)]3[H3O]2[Cd6Br(H2-DHBDC)8(DMF)4] (1; H4-DHBDC=2,5-dihydroxy-1,4-benzenedicarboxylic acid, DMF=N,N-dimethylformamide) and [(CH3)2NH2]2[Cd3(H2-DHBDC)4(DMF)2]·2DMF(2), are prepared from the self-assembly reactions between Cd(CH3COO)2 and H4-DHBDC, respectively. Both anionic frameworks consist of linear trinuclear Cd units (e.g., 1: [Cd3BrO2(CO2)7] and [Cd3O2(CO2)8]; 2: [Cd3O2(CO2)8]) linked by the H2-DHBDC ligands. The photoluminescent properties of compound 1 are tunable through cation-exchange with different metal ions. The results demonstrated an effective ion-exchange approach toward the functional modification of MOF materials.

Reported here is a versatile method capable of generating pore space partition in zeolitic boron imidazolate frameworks (BIFs), which is based on the coexistence of presynthesized boron imidazolate complexes and charge balancing carboxylate ligands. Using this method, boron imidazolate complexes are used to form zeolitic nets, while the carboxylate serves to partition large channel spaces into multiple domains. The generality of this method is shown by two distinct boron imidazolate frameworks mimicking GIS (BIF-41) and ABW (BIF-42) zeotype topologies. BIF-41 shows high selectivity sorption of CO2 over N2.

Two Ag(I)-imidazolate compounds with distinct chain-like structures, namely, [Ag(dm-bim)]n (1, dm-bim = 5,6-dimethylbenzimidazole) and [Ag(m-bim)]n (2, m-bim = 2-methylbenzimidazole), were synthesized and structurally characterized, respectively. Compound 1 with helical chains exhibited unique luminescence mechanochromism due to short Ag⋯Ag interactions (2.986 A).

Urban vegetation can influence local air temperatures through its biophysical effects on surface energy balance. These effects produce gradients (ΔTa) between air temperature of vegetation spaces (Tveg) and air temperature of open spaces (Topen) ( Δ T a = T v e g − T o p e n ), hereafter referred to as vegetation cooling (negative values of ΔTa) and warming (positive values of ΔTa), respectively. But vegetation cooling or warming highly depends on background climate of urban areas as well as on vegetation states. Field observations are usually restricted to one or few cities, setting limitations to a general understanding. In this study, a synthetic analysis of 3634 point-scale in-situ observations from 77 global sites in 35 cites was conducted using the bootstrap sampling and hierarchical partitioning methods. Results show that vegetation cooling is generally stronger during the daytime periods, in warm seasons, at low latitude zones, for forest lands and at leaf growth stage, while vegetation warming usually occurs in the opposite contexts. Urban vegetation begins to exert considerable cooling effects when the daily mean background air temperature (BAT) is >10.0 °C, but on average has a slight warming effect when BAT is °C. Besides, vegetation cooling increases sharply when evapotranspiration is >61.7 mm/month or when area of urban vegetation is >35.2 ha. Plant growth stages (i.e., canopy leaf growth, senescence and dormancy stages) (37.6 ± 0.11%), a vegetation phenology proxy, acts as the primary biotic factor, while seasonality (23.0 ± 0.11%) and latitude (11.4 ± 0.07%) that control the background climate are two most important abiotic contributors. Our findings suggest approximate thresholds for distinguishing vegetation cooling/warming effects and provide helpful information for future urban greenspace planning aimed at mitigating local climate warming.

Cellular senescence is an irreversible cell cycle arrest process associated with aging and senescence-related diseases. DNA damage is an extensive feature of cellular senescence and aging. Different levels of DNA damage could lead to cellular senescence or transient cell-cycle arrest, but the genetic regulatory mechanisms determining cell fate are still not clear. In this work, high-resolution time course analysis of gene expression in DNA damage-induced cellular senescence and transient cell-cycle arrest was used to explore the transcriptomic differences between different cell fates after DNA damage response and to investigate the key regulatory factors affecting senescent cell fates. Pathways such as the cell cycle, DNA repair and cholesterol metabolism showed characteristic differential response. A number of key transcription factors were predicted to regulating cell cycle and DNA repair. Our study provides genome-wide insights into the molecular-level mechanisms of senescent cell fate decisions after DNA damage response.

Presented here is an interpenetrated three-dimensional copper-iodine cluster-based framework with dia topology based on two different kinds of Cu4I4 subunits that is templated by an enantiopure porphyrin-like Cu(I)(5-eatz)2 unit and shows excellent photocatalytic activity to degrade methylene blue under visible light.

By employment of predesigned proline derivative ligands ((R)-PIA and (S)-PIA) to assemble with bipy and Cd2+ ion, a pair of porous homochiral metal–organic frameworks (HMOFs) with a wavy Cd-PIA layer has been synthesized.

Satellite-based drought indices have been proved to be effective and convenient in detecting drought conditions at regional and global scales. However, most current drought indices are based on the visible/near infrared/thermal remote sensing, which might be influenced greatly by cloud, atmospheric water content and rain-fall. Microwave sensors can overcome the shortages of visible/near infrared/thermal remote sensing and show to be another important approach for drought monitoring due to its all-weather working advantages. But to date, the application of microwave vegetation drought indices in drought monitoring has not been thoroughly investigated. Here, for the first time we constructed a microwave derived Temperature Vegetation Drought Index (TVDI) - MTVDI based on the theory of optical TVDI using the brightness temperatures (Tb) from the Advanced Microwave Scanning Radiometer (AMSR ‐ E) onboard Aqua satellite. Firstly, we built a new land surface temperature (Ts) inversion model based on the AMSR ‐ E 18.7 GHz horizontal, 23.8 GHz and 89.0 GHz vertical polarized Tb, and then developed the Microwave Normalized Difference Vegetation Index (MNDVI) from the AMSR ‐ E 23.8 GHz Microwave Polarization Difference Index (MPDI). After that, we constructed three versions of MTVDI: original MTVDI using Ts and MNDVI; Imp ‐ MTVDI (Improved MTVDI) using the Ts ‐ Tair (the difference between land surface temperature and air temperature) to replace the Ts; and NonL ‐ MTVDI (Nonlinear MTVDI) using nonlinear equation to fit the dry and wet edges, respectively. Finally, we used precipitation, soil moisture (SM) and P/PET (the ratio of precipitation to potential evapotranspiration) to validate the performances of MTVDI, Imp ‐ MTVDI, NonL ‐ MTVDI, MODIS derived TVDI and iTVDI (improved TVDI). The time-series drought assessments across China from 2003 to 2010 indicated that the trends of the proposed MTVDI showed the most negative correlations with the variations of precipitation, P/PET and SM, and showed best performances of significance test in most regions of China. Moreover, the MTVDI could better separate the drought levels in different degrees than MODIS-derived TVDI. However, the proposed MTVDI still has some uncertainties in regions widely covered by desert, Gobi and large water surfaces. In addition, this paper mainly focuses on large spatial scale and long term drought monitoring and only uses satellite data for model validation. Further studies are needed to develop a higher spatial- and temporal-resolution MTVDI for short-term and small spatial-scale drought monitoring.

We present a highly selective and sensitive colorimetric method for the detection of selenocystine (SeCys) coexisting with other amino acids, especially cysteine (Cys) using the gold nanoparticles (AuNPs). Firstly, Cys was oxidized to cystine (Cys-Cys) by dissolved oxygen under Cu2+ catalysis in the pre-reaction, which eliminated the interference of Cys in the SeCys sensing process. Then SeCys induced the rapid aggregation of AuNPs through Au-Se bond and complex formation of Cu2+-SeCys in the colorimetric reaction, in which the color change of AuNPs from red to blue or purple with the naked eye detection or with a UV-vis spectrophotometric determination. The concentration of SeCys was quantified by the value at 670 nm from the second-derivative SPR absorbance spectrum. The linear range was from 2 μM to 14 μM with correlation coefficient of 0.999 and a detection limit (LOD) was 0.14 μM. Moreover, the colorimetric response of AuNPs exhibited remarkable specificity to SeCys coexisting with 18 amino acids in a simulation sample, in which the total concentration of Cys and Cys-Cys was less than 15 μM and the each concentration of other 16 common amino acids was 10 μM.

The well-documented energy balance dynamics within forest ecosystems are poorly implemented in studies of the biophysical effects of forests. This results in limitations to the accurate quantification of forest cooling/warming on local air temperature. Taking into consideration the forest air space, this study proposes a three-layered (canopy, forest air space and soil [CAS]) land surface energy balance model to simulate air temperature within forest spaces (Taf) and subsequently to evaluate its biophysical effects on forest cooling/warming, i.e., the air temperature gradient (∆Ta) between the Taf and air temperature of open spaces (Tao) (∆Ta = Taf − Tao). We test the model using field data for 23 sites across 10 cities worldwide; the model shows satisfactory performance with the test data. High-latitude forests show greater seasonal dynamics of ∆Ta, generating considerable cooling of local air temperatures in warm seasons but minimal cooling or even warming effects during cool seasons, while low-latitude tropical forests always exert cooling effects with less interannual variability. The interannual dynamics of ∆Ta are significantly related to the seasonality of solar geometry and canopy leaf phenology. The differences between forest canopy temperature (Tc) and Tao, which are the two most important terms attributed by the CAS model in impacting Taf, explain a large part of forest cooling and warming (May–July: R2 = 0.35; November–January: R2 = 0.51). The novel CAS model provides a feasible way to represent the energy balance within forest ecosystems and to assess its impacts on local air temperatures globally. Keywords: Forest cooling/warming, Forest biophysical effects, Radiative transfer equation, Land-atmosphere model, Local environmental health, Climate warming mitigation

Using lactic acid derivatives as chiral ligands, a pair of unprecedented homochiral metal–organic zeolites have been synthesized that feature zeotype CAN topology and have high porosity for enantioselective separation of racemates.

A series of zirconium polyphenolate-decorated-(metallo)porphyrin metal-organic frameworks (MOFs), ZrPP-n (n = 1, 2), featuring infinite ZrIV -oxo chains linked via polyphenolate groups on four peripheries of eclipse-arranged porphyrin macrocycles, are successfully constructed through a top-down process from simulation to synthesis. These are the unusual examples of Zr-MOFs (or MOFs in general) based on phenolic porphyrins, instead of commonly known carboxylate-based types. Representative ZrPP-1 not only exhibits strong acid resistance (pH = 1, HCl) but also remains intact even when immersed in saturated NaOH solution (≈20 m), an exceptionally large range of pH resistance among MOFs. The metallation at the porphyrin core gives rise to materials with enhanced sorption and catalytic properties. In particular, ZrPP-1-Co, with precise and uniform distribution of active centers, exhibits not only high CO2 trapping capability (≈90 cm3 g-1 at 1 atm, 273 K, among the highest in Zr-MOFs) but also high photocatalytic activity for reduction of CO2 into CO (≈14 mmol g-1 h-1 ) and high selectivity over CH4 (>96.4%) without any cocatalyst under visible-light irradiation (λ > 420 nm). Given the strong chemical resistance under extreme alkali conditions, these catalysts can be recycled without appreciable loss of activity. The possible mechanism for photocatalytic reduction of CO2 -to-CO over ZrPP-1-Co is also proposed.

Investigating the spatiotemporal changes of regional surface soil moisture in responses to climate and land cover changes is vital for understanding the underlying mechanisms of hydrological processes. While previous studies mainly attributed the causes of soil moisture changes to climatic factors, few took land cover into consideration. We analyzed the seasonal-differentiated effects of climate and land cover changes on surface soil moisture of China's 80 drainage basins using the Essential Climate Variable Soil Moisture (ECV_SM) product spanning the 1979-2010 period. The low-low spatial clusters of annual (Jan ~ Dec), warm-season (Apr ~ Sept) and cool-season (Oct ~ Dec, Jan ~ Mar) surface soil moisture have spread from northwest China to northeast and even central China during past three decades. In cool seasons, significant decreasing trends of surface soil moisture in most drainage basins of northwest, northeast, central and south China were detected. But in warm seasons, the surface soil moisture in central and south China showed significant increasing trends. Precipitation, potential evapotranspiration and the ratio of the two are three driving forces for warm-season surface soil moisture changes in northeast and northwest China. These climatic factors are main contributors to the declining trends of cool-season surface soil moisture in central and south China. Land cover changes showed to be the major factor driving the significant decreasing trends of cool-season surface soil moisture in northwest, central and south China. Due to vegetation's self-shading effect, the large-scale reforestation and vegetation growth are believed as main causes of the increasing trends of warm-season surface soil moisture in central and south China.