scholarly journals Spatio-Temporal Variation in AOD and Correlation Analysis with PAR and NPP in China from 2001 to 2017

2020 ◽  
Vol 12 (6) ◽  
pp. 976 ◽  
Author(s):  
Xin Li ◽  
Hongyu Liang ◽  
Weiming Cheng
Keyword(s):  
Net Primary Productivity ◽  
Negative Impact ◽  
Positive Impact ◽  
Ground Surface ◽  
Terrestrial Ecosystems ◽  
Temporal Variations ◽  
Plant Production ◽  
Positive Correlation ◽  
Increasing Trend ◽  
Spatio Temporal

Atmospheric aerosols can elicit variations in how much solar radiation reaches the ground surface due to scattering and absorption, which may affect plant photosynthesis and carbon uptake in terrestrial ecosystems. In this study, the spatio-temporal variations in aerosol optical depth (AOD) are compared with that in photosynthetically active radiation (PAR) and net primary productivity (NPP) during 2001–2017 in China using multiple remote sensing data. The correlations between them are analyzed at different scales. Overall, the AOD exhibited a northeast-to-southwest decreasing pattern in space. A national increasing trend of 0.004 year−1 and a declining trend of −0.007 year−1 of AOD are observed during 2001–2008 and 2009–2017. The direct PAR (PARdir) and diffuse PAR (PARdif) present consistent and opposite tendency with AOD during two periods, respectively. The total PAR (PARtotal) shows a similar variation pattern with PARdir. In terms of annual variation, the peaks of AOD coincide with the peaks of PARdif and the troughs of PARdir, indicating that aerosols have a significant positive impact on PARdir and a negative impact on PARdif. Furthermore, the PARdir has a stronger negative association with AOD than the positive correlation between PARdif and AOD at national and regional scales, indicating that PARdir is more sensitive to aerosol changes. The NPP has higher values in the east than in the west and exhibits a significant increasing trend of 0.035 gCm−2day−1 after 2008. The NPP has a negative correlation (−0.4–0) with AOD and PARdif and a positive correlation (0–0.4) with PARdir in most areas of China. The area covered by forests has the highest NPP-PAR correlation, indicating that NPP in forests is more sensitive to the PAR than is the NPP in grasslands and croplands. This study is beneficial for interpreting the aerosol-induced PAR impact on plant growth and for predicting plant production on haze days.

scholarly journals Drought-Induced Reduction in Net Primary Productivity across Mainland China from 1982 to 2015

2018 ◽  
Vol 10 (9) ◽  
pp. 1433 ◽  
Author(s):  
Chengguang Lai ◽  
Jun Li ◽  
Zhaoli Wang ◽  
Xiaoqing Wu ◽  
Zhaoyang Zeng ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Mainland China ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Tibet Plateau ◽  
Positive Correlation ◽  
Casa Model ◽  
Increasing Trend ◽  
Qinghai Tibet Plateau

Terrestrial net primary productivity (NPP) plays an essential role in the global carbon cycle as well as for climate change. However, in the past three decades, terrestrial ecosystems across mainland China suffered from frequent drought and, to date, the adverse impacts on NPP remain uncertain. This study explored the spatiotemporal features of NPP and discussed the influences of drought on NPP across mainland China from 1982 to 2015 using the Carnegie Ames Stanford Application (CASA) model and the standardized precipitation evapotranspiration index (SPEI). The obtained results indicate that: (1) The total annual NPP across mainland China showed an non-significantly increasing trend from 1982 to 2015, with annual increase of 0.025 Pg C; the spring NPP exhibited a significant increasing trend (0.031 Pg C year−1, p < 0.05) while the summer NPP showed a higher decreasing trend (0.019 Pg C year−1). (2) Most areas of mainland China were spatially dominated by a positive correlation between annual NPP and SPEI and a significant positive correlation was mainly observed for Northern China; specific to the nine sub-regions, annual NPP and SPEI shared similar temporal patterns with a significant positive relation in Northeastern China, Huang-Huai-Hai, Inner Mongolia, and the Gan-Xin Region. (3) During the five typical drought events, more than 23% areas of mainland China experienced drought ravage; the drought events generally caused about 30% of the NPP reduction in most of the sub-regions while the NPP in the Qinghai-Tibet Plateau Region generally decreased by about 10%.

scholarly journals Environmental controls on the increasing GPP of terrestrial vegetation across northern Eurasia

2016 ◽  
Vol 13 (1) ◽  
pp. 45-62 ◽  
Author(s):  
P. Dass ◽  
M. A. Rawlins ◽  
J. S. Kimball ◽  
Y. Kim
Keyword(s):  
Forest Fires ◽  
Environmental Control ◽  
Negative Impact ◽  
Positive Impact ◽  
Terrestrial Ecosystems ◽  
Northern Eurasia ◽  
Terrestrial Vegetation ◽  
The South ◽  
Environmental Controls ◽  
Significant Negative Impact

Abstract. Terrestrial ecosystems of northern Eurasia are demonstrating an increasing gross primary productivity (GPP), yet few studies have provided definitive attribution for the changes. While prior studies point to increasing temperatures as the principle environmental control, influences from moisture and other factors are less clear. We assess how changes in temperature, precipitation, cloudiness, and forest fires individually contribute to changes in GPP derived from satellite data across northern Eurasia using a light-use- efficiency-based model, for the period 1982–2010. We find that annual satellite-derived GPP is most sensitive to the temperature, precipitation and cloudiness of summer, which is the peak of the growing season and also the period of the year when the GPP trend is maximum. Considering the regional median, the summer temperature explains as much as 37.7 % of the variation in annual GPP, while precipitation and cloudiness explain 20.7 and 19.3 %. Warming over the period analysed, even without a sustained increase in precipitation, led to a significant positive impact on GPP for 61.7 % of the region. However, a significant negative impact on GPP was also found, for 2.4 % of the region, primarily the dryer grasslands in the south-west of the study area. For this region, precipitation positively correlates with GPP, as does cloudiness. This shows that the south-western part of northern Eurasia is relatively more vulnerable to drought than other areas. While our results further advance the notion that air temperature is the dominant environmental control for recent GPP increases across northern Eurasia, the role of precipitation and cloudiness can not be ignored.

Spatio-temporal variation in NPP and correlation analysis with aerosol loading and PAR in China during 2001-2017

2020 ◽  
Author(s):  
Xin Li ◽  
Weiming Cheng
Keyword(s):  
Temporal Variation ◽  
Net Primary Productivity ◽  
Terrestrial Ecosystems ◽  
Terrestrial Vegetation ◽  
Significance Level ◽  
Aerosol Loading ◽  
Western Yunnan ◽  
Growth Respiration ◽  
Spatio Temporal ◽  
The Difference

&lt;p&gt;The net primary productivity (NPP) reflects the growth or production of terrestrial vegetation and plays an important role in the carbon cycle on the earth. It quantifies the difference between the organic matter produced by photosynthesis and the loss of maintenance and growth respiration. The investigation of the spatio-temporal variation in NPP is significant for monitoring plant photosynthesis and carbon uptake in terrestrial ecosystems. In this study, the variability and trend of NPP in China during 2001-2017 are analysed using level 4 MODIS product (MOD17A2H). Additionally, to explore whether the NPP change in recent decades are related with the photosynthetically active radiation (PAR) variation caused by increasing aerosol loading, the correlation between NPP, PAR and aerosol optical depth (AOD) are analysed at national, regional, and pixel scales. The results show that the annual mean NPP shows higher values in the southeast than in the northwest. The highest NPP level above 2.5 gCm&lt;sup&gt;-2&lt;/sup&gt;day&lt;sup&gt;-1&lt;/sup&gt; is mainly distributed in tropical humid regions, including Zhejiang, Fujian, Guangdong and western Yunnan. The NPP increases with an amplitude of 0.131 gCm&lt;sup&gt;-2&lt;/sup&gt;day&lt;sup&gt;-1&lt;/sup&gt; during the study period. The forests have higher mean levels of NPP (1.808 gCm&lt;sup&gt;-2&lt;/sup&gt;day&lt;sup&gt;-1&lt;/sup&gt;) and larger increasing magnitudes (0.35 gCm&lt;sup&gt;-2&lt;/sup&gt;day&lt;sup&gt;-1&lt;/sup&gt;) than those of croplands and grasslands. The NPP and AOD show a negative correlation (-0.6&lt;R&lt;-0.2) at a significance level of 0.05 over the middle area of China. The PAR direct and diffuse components generally have positive (0&lt;R&lt;sub&gt;PARdir_NPP&lt;/sub&gt;&lt;0.6) and negative correlations (-0.6&lt;R&lt;sub&gt;PARdif_NPP&lt;/sub&gt;&lt;0) with NPP, respectively, in most of China except the northeast and Tibetan Plateau. The NPP have stronger correlations (0.215 and -0.218) with the direct and diffuse PAR in forests than in croplands and grasslands, implying that NPP is more sensitive to the change in PAR in forests than in other vegetation cover types.&lt;/p&gt;

scholarly journals The Influence of Motivation, Attitudes and Obstacles for Middle School Students’ Participation in Leisure Activities on Their Leisure Satisfaction in Southwest China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yunlan Wu ◽  
Jianan Sun ◽  
Falu Fan ◽  
Xia Wang ◽  
Yuanqiu Peng
Keyword(s):  
Middle School ◽  
Factor Analysis ◽  
Middle School Students ◽  
Negative Impact ◽  
Positive Impact ◽  
Direct Impact ◽  
Leisure Satisfaction ◽  
School Students ◽  
Positive Correlation ◽  
Leisure Motivation

Purpose: To explore the relationship among leisure motivation, barriers, attitude and satisfaction of middle school students in Chengdu, Sichuan, to help students establish a positive leisure attitude and provide a reference for youth leisure counseling.Methods: Based on consulting research literature, this paper designs a survey volume of teenagers’ leisure motivation, barriers, attitude, and satisfaction; 2249 valid questionnaires of middle school students in Chengdu were obtained by stratified random sampling. The data were statistically processed by the combination of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA).Results: (1) There are significant positive correlation effects between leisure motivation and leisure attitude, leisure attitude and leisure satisfaction, and leisure motivation and leisure satisfaction; (2) There is a low degree of positive correlation effect (r = 0.35 *) between leisure barriers and leisure motivation, which is contrary to common sense and needs to be further studied in the follow-up; (3) Leisure barriers has no significant direct impact on leisure satisfaction, but it can have a significant negative impact on leisure satisfaction with the intermediary variable of leisure attitude; (4) Leisure motivation is the most important variable in the whole leisure model structure. It not only has the greatest direct impact on leisure satisfaction but also has a great positive impact on leisure satisfaction through the intermediary of leisure attitude.Conclusion: Adolescent leisure motivation, barriers, attitude, and satisfaction are complementary and interdependent. Among them, leisure motivation is the core variable and leisure attitude is the dual intermediary variable. Through the initiation of leisure motivation, helping adolescents establish a positive leisure attitude may be the key to ensure their leisure satisfaction.

scholarly journals Evaluation of Future Impacts of Climate Change, CO2, and Land Use Cover Change on Global Net Primary Productivity Using a Processed Model

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 365
Author(s):  
Xiao Hu ◽  
Yujie He ◽  
Ze Kong ◽  
Jiang Zhang ◽  
Minshu Yuan ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Positive Impact ◽  
Positive Contribution ◽  
Increasing Trend ◽  
Tropical Areas ◽  
The Impact ◽  
Positive Effect

Few studies have focused on the combined impact of climate change, CO2, and land-use cover change (LUCC), especially the evaluation of the impact of LUCC on net primary productivity (NPP) in the future. In this study, we simulated the overall NPP change trend from 2010 to 2100 and its response to climatic factors, CO2 concentration, and LUCC conditions under three typical emission scenarios (Representative Concentration Pathway RCP2.6, RCP4.5, and RCP8.5). (1) Under the predicted global pattern, NPP showed an increasing trend, with the most prominent variation at the end of the century. The increasing trend is mainly caused by the positive effect of CO2 on NPP. However, the increasing trend of LUCC has only a small positive effect. (2) Under the RCP 8.5 scenario, from 2090 to 2100, CO2 has the most significant positive impact on tropical areas, reaching 8.328 Pg C Yr−1. Under the same conditions, climate change has the greatest positive impact on the northern high latitudes (1.175 Pg C Yr−1), but it has the greatest negative impact on tropical areas, reaching −4.842 Pg C Yr−1. (3) The average contribution rate of LUCC to NPP was 6.14%. Under the RCP8.5 scenario, LUCC made the largest positive contribution on NPP (0.542 Pg C Yr−1) globally from 2010 to 2020.

scholarly journals Spatio-Temporal Grassland Development in Inner Mongolia after Implementation of the First Comprehensive Nation-Wide Grassland Conservation Program

Land ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 38
Author(s):  
Zhichao Xue ◽  
Martin Kappas ◽  
Daniel Wyss
Keyword(s):  
Inner Mongolia ◽  
Net Primary Productivity ◽  
Positive Impact ◽  
Meteorological Data ◽  
Impact Factors ◽  
Desert Grassland ◽  
Major Step ◽  
Grassland Conservation ◽  
Spatio Temporal ◽  
Moderate Resolution Imaging Spectroradiometer

Protection of the grassland’s ecological environment and improvement of people’s livelihoods are major tasks for the management of pastoral areas in Inner Mongolia. The comprehensive program for grassland conservation in China, the Subsidy and Incentive System for Grassland Conservation (SISGC), was launched in 2011. To comprehend the effects of this major step towards sustainable grassland development, this study focuses on the spatio-temporal development of grasslands in Inner Mongolia since 2011. Through the combination of MODIS (Moderate-resolution Imaging Spectroradiometer) satellite data with up to date meteorological data, we used the indicators of Fractional Vegetation Cover (FVC) and Net Primary Productivity (NPP) to analyze qualitative and quantitative grassland changes. A classification system on the pixel level, reflecting change trends and fluctuations of both FVC and NPP, was applied to monitor and analyze the grassland development from 2011 to 2019. In particular, the spatial transfer matrix of the recent two years (2018 to 2019) was analyzed to reveal the latest potential issues and random impact factors. The results show a positive overall but spatially unbalanced effect of SISGC, with a prominent positive impact in the semi-desert grassland area. The potential threats from both social and natural aspects as well as the importance of a forecast system for local stakeholders in the pastoral area are discussed.

Spatio-temporal variations of net primary productivity and its natural and human factors analysis in Qinling-Daba Mountains in the past 15 years

2019 ◽  
Vol 39 (22) ◽  
Author(s):  
李金珂 LI Jinke ◽  
杨玉婷 YANG Yuting ◽  
张会茹 ZHANG Huiru ◽  
黄铝文 HUANG Lüwen ◽  
高义民 GAO Yimin
Keyword(s):  
Human Factors ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Temporal Variations ◽  
The Past ◽  
Factors Analysis ◽  
Spatio Temporal ◽  
Human Factors Analysis

scholarly journals Projection of Net Primary Productivity under Global Warming Scenarios of 1.5 °C and 2.0 °C in Northern China Sandy Areas

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 71 ◽  
Author(s):  
Xiaofei Ma ◽  
Tianci Huo ◽  
Chengyi Zhao ◽  
Wei Yan ◽  
Xun Zhang
Keyword(s):  
Global Warming ◽  
Primary Productivity ◽  
Net Primary Productivity ◽  
Negative Impact ◽  
Northern China ◽  
Inhibitory Effect ◽  
Emission Scenarios ◽  
Casa Model ◽  
Spatio Temporal ◽  
The Impact

Empirical evidence suggests that variations in climate affect the net primary productivity (NPP) across sandy areas over time. However, little is known about the relative impacts of climate change on NPP with global warming of 1.5 and 2.0 °C (GW_1.5 °C_2.0 °C) relative to pre-industrial levels. Here, we used a new set of climate simulations from four Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP 2b) datasets, modified the Carnegie-Ames-Stanford approach (CASA) model and assessed the spatio-temporal variation in NPP in sandy areas of northern China (SAONC). Compared with the reference period (RP, 1986–2005), the NPP variation under four emission scenarios showed clear rising trends and increased most significantly under RCP8.5 with an annual average increase of 2.34 g C/m2. The estimated annual NPP under global warming of 1.5 °C (GW_1.5 °C) increased by 14.17, 10.72, 8.57, and 26.68% in different emission scenarios, and under global warming of 2.0 °C (GW_2.0 °C) it increased by 20.87, 24.01, 29.31, and 39.94%, respectively. In terms of seasonal change, the NPP value under the four emission scenarios changed most significantly in the summer relative to RP, exhibiting a growth of 16.48%. Temperature changes (p > 0.614) had a greater impact on NPP growth than precipitation (p > 0.017), but solar radiation showed a certain negative impact in the middle- and low-latitude regions. NPP showed an increasing trend that changed from the southeast to the central and western regions at GW_1.5 to GW_2.0 °C. NPP was consistent with the spatial change in climate factors and had a promoting role in high latitudes in SAONC, but it was characterized by a certain inhibitory effect at middle and low latitudes in SAONC. The uncertainty of NPP under the four models ranged from 16.29 to 26.52%. Our findings suggest that the impact of GW_1.5 °C is relatively high compared with the current conditions, whereas GW_2.0 °C implies significantly lower projected NPP growth in all areas.

scholarly journals Abortion and infant mortality change driven by socioeconomic conditions in Russia

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Li Wang ◽  
Linsheng Yang ◽  
Hairong Li ◽  
Hongyan Cai ◽  
Jixia Huang ◽  
...  
Keyword(s):  
Infant Mortality ◽  
Negative Impact ◽  
Positive Impact ◽  
Infant Mortality Rate ◽  
Socioeconomic Conditions ◽  
Per Capita ◽  
Spatio Temporal ◽  
Using Data ◽  
Regional Product ◽  
The Impact

Increasing fertility and decreasing mortality are major response strategies in Russian demographic reform, which has led to significant decreases in both abortion rate (AR) and infant mortality. This study explores mechanisms influencing the socioeconomic conditions leading to abortion and infant mortality. Spatial panel economic analysis using data from the 83 regions of the country covering four time periods was applied. Every 1000 USD increase in per capita gross regional product (GRP) can lead to a decrease of the AR by 0.075, while one year life expectancy increase would lower it by 0.441. For infant mortality rate (IMR), GRP also shows a positive impact, particularly in recent years, while the population size of the region has a negative impact. Every 1000 USD increase in per capita GRP would result in a rate decrease of 0.064 in IMR, and every increase of 1000 added population would lead to an increased IMR by 2.05. The harvest effect between AR and infant mortality that was evident earlier, but not in the recent years, implies that the health care system in Russia is effective. A comprehensive improvement in wellbeing, income, etc. can contribute to mitigation of abortion and infant mortality. Theoretically, this study extends current research by comprehensively displaying the spatio-temporal patterns of abortion and infant mortality in Russia and qualifies the impact of regional socioeconomic disparities with regard to these two issues.

scholarly journals Assessing Terrestrial Ecosystem Resilience using Satellite Leaf Area Index

2020 ◽  
Vol 12 (4) ◽  
pp. 595
Author(s):  
Jinhui Wu ◽  
Shunlin Liang
Keyword(s):  
Positive Impact ◽  
Terrestrial Ecosystem ◽  
Remote Sensing Data ◽  
Terrestrial Ecosystems ◽  
Temporal Variations ◽  
Global Scale ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Ecosystem Resilience ◽  
Area Index

Quantitative approaches to measuring and assessing terrestrial ecosystem resilience, which expresses the ability of an ecosystem to recover from disturbances without shifting to an alternative state or losing function and services, is critical and essential to forecasting how terrestrial ecosystems will respond to global change. However, global and continuous terrestrial resilience measurement is fraught with difficulty, and the corresponding attribution of resilience dynamics is lacking in the literature. In this study, we assessed global terrestrial ecosystem resilience based on the long time-series GLASS LAI product and GIMMS AVHRR LAI 3g product, and validated the results using drought and fire events as the main disturbance indicators. We also analyzed the spatial and temporal variations of global terrestrial ecosystem resilience and attributed their dynamics to climate change and environmental factors. The results showed that arid and semiarid areas exhibited low resilience. We found that evergreen broadleaf forest exhibited the highest resilience (mean resilience value (from GLASS LAI): 0.6). On a global scale, the increase of mean annual precipitation had a positive impact on terrestrial resilience enhancement, while we found no consistent relationships between mean annual temperature and terrestrial resilience. For terrestrial resilience dynamics, we observed three dramatic raises of disturbance frequency in 1989, 1995, and 2001, respectively, along with three significant drops in resilience correspondingly. Our study mapped continuous spatiotemporal variation and captured interannual variations in terrestrial ecosystem resilience. This study demonstrates that remote sensing data are effective for monitoring terrestrial resilience for global ecosystem assessment.

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