Land surface phenology from Copernicus Global Land time series

Bornez, K., Verger, A., Filella, I., Penuelas, J. (2017) Land surface phenology from Copernicus Global Land time series. 2017 9th International Workshop on the Analysis of Multitemporal Remote Sensing Images, MultiTemp 2017. : 0-0.
Link
Doi: 10.1109/Multi-Temp.2017.8035262

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Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa

Brandt, M., Rasmussen, K., Peñuelas, J., Tian, F., Schurgers, G., Verger, A., Mertz, O., Palmer, J.R.B., Fensholt, R. (2017) Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa. Nature Ecology and Evolution. 1: 0-0.
Link
Doi: 10.1038/s41559-017-0081

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Atmospheric deposition, CO2, and change in the land carbon sink

Fernández-Martínez M., Vicca S., Janssens I.A., Ciais P., Obersteiner M., Bartrons M., Sardans J., Verger A., Canadell J.G., Chevallier F., Wang X., Bernhofer C., Curtis P.S., Gianelle D., Grünwald T., Heinesch B., Ibrom A., Knohl A., Laurila T., Law B.E., Limousin J.M., Longdoz B., Loustau D., Mammarella I., Matteucci G., Monson R.K., Montagnani L., Moors E.J., Munger J.W., Papale D., Piao S.L., Peñuelas J. (2017) Atmospheric deposition, CO2, and change in the land carbon sink. Scientific Reports. 7: 0-0.
Link
Doi: 10.1038/s41598-017-08755-8

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Concentrations of atmospheric carbon dioxide (CO2) have continued to increase whereas atmospheric deposition of sulphur and nitrogen has declined in Europe and the USA during recent decades. Using time series of flux observations from 23 forests distributed throughout Europe and the USA, and generalised mixed models, we found that forest-level net ecosystem production and gross primary production have increased by 1% annually from 1995 to 2011. Statistical models indicated that increasing atmospheric CO2 was the most important factor driving the increasing strength of carbon sinks in these forests. We also found that the reduction of sulphur deposition in Europe and the USA lead to higher recovery in ecosystem respiration than in gross primary production, thus limiting the increase of carbon sequestration. By contrast, trends in climate and nitrogen deposition did not significantly contribute to changing carbon fluxes during the studied period. Our findings support the hypothesis of a general CO2-fertilization effect on vegetation growth and suggest that, so far unknown, sulphur deposition plays a significant role in the carbon balance of forests in industrialized regions. Our results show the need to include the effects of changing atmospheric composition, beyond CO2, to assess future dynamics of carbon-climate feedbacks not currently considered in earth system/climate modelling. © 2017 The Author(s).

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Assessment of Three Methods for Near Real-Time Estimation of Leaf Area Index from AVHRR Data

Kandasamy S., Verger A., Baret F. (2017) Assessment of Three Methods for Near Real-Time Estimation of Leaf Area Index from AVHRR Data. IEEE Transactions on Geoscience and Remote Sensing. 55: 1489-1497.
Link
Doi: 10.1109/TGRS.2016.2626307

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Near real-time (NRT) estimation of leaf area index (LAI) is essential for monitoring rapid surface process changes within operational systems. This paper assesses the performances of three methods for the NRT estimation of LAI: 1) Whittaker (Whit); 2) Gaussian process model (GPM); and 3) the climatological temporal smoothing and gap filling (CTSGF). The methods were evaluated using Advanced Very High Resolution Radiometer time series over a selection of BELMANIP2 sites representative of seasonal patterns of global biome vegetated areas and under varying level of noise and missing observations (gaps). A simulation experiment was designed to evaluate the predictive capabilities of the three methods with an emphasis on the global and local structure of missing observations in the time series. The results show that the three methods achieve similar performances (RMSE

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Impacts of global change on Mediterranean forests and their services

Peñuelas, J., Sardans, J., Filella, I., Estiarte, M., Llusià, J., Ogaya, R., Carnicer, J., Bartrons, M., Rivas-Ubach, A., Grau, O., Peguero, G., Margalef, O., Pla-Rabés, S., Stefanescu, C., Asensio, D., Preece, C., Liu, L., Verger, A., Barbeta, A., Achotegui-Castells, A., Gargallo-Garriga, A., Sperlich, D., Farré-Armengol, G., Fernández-Martínez, M., Liu, D., Zhang, C., Urbina, I., Camino-Serrano, M., Vives-Ingla, M., Stocker, B.D., Balzarolo, M., Guerrieri, R., Peaucelle, M., Marañón-Jiménez, S., Bórnez-Mejías, K., Mu, Z., Descals, A., Castellanos, A., Terradas, J. (2017) Impacts of global change on Mediterranean forests and their services. Forests. 8: 0-0.
Link
Doi: 10.3390/f8120463

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Spatiotemporally representative and cost-efficient sampling design for validation activities in wanglang experimental site

Yin, G., Li, A., Verger, A. (2017) Spatiotemporally representative and cost-efficient sampling design for validation activities in wanglang experimental site. Remote Sensing. 9: 0-0.
Link
Doi: 10.3390/rs9121217

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