scholarly journals Surface Albedo Response to Sahel Precipitation Changes

Eos ◽  
2007 ◽  
Vol 88 (3) ◽  
pp. 25 ◽  
Author(s):  
Yves Govaerts ◽  
Alessio Lattanzio
Keyword(s):  
Surface Albedo ◽  
Precipitation Changes ◽  
Sahel Precipitation

Quantification of temperature and precipitation changes in northern China during the “5000-year” Chinese History

2021 ◽  
Vol 255 ◽  
pp. 106819 ◽  
Author(s):  
Can Zhang ◽  
Cheng Zhao ◽  
Aifeng Zhou ◽  
Haixia Zhang ◽  
Weiguo Liu ◽  
...  
Keyword(s):  
Northern China ◽  
Chinese History ◽  
Temperature And Precipitation ◽  
Precipitation Changes

scholarly journals Assessment of the EUMETSAT Multi Decadal Land Surface Albedo Data Record from Meteosat Observations

2021 ◽  
Vol 13 (10) ◽  
pp. 1992
Author(s):  
Alessio Lattanzio ◽  
Michael Grant ◽  
Marie Doutriaux-Boucher ◽  
Rob Roebeling ◽  
Jörg Schulz
Keyword(s):  
Land Surface ◽  
Surface Albedo ◽  
Time Range ◽  
Essential Variable ◽  
Spatial Coverage ◽  
Data Record ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Mask ◽  
Cloud Screening

Surface albedo, defined as the ratio of the surface-reflected irradiance to the incident irradiance, is one of the parameters driving the Earth energy budget and it is for this reason an essential variable in climate studies. Instruments on geostationary satellites provide suitable observations allowing long-term monitoring of surface albedo from space. In 2012, EUMETSAT published Release 1 of the Meteosat Surface Albedo (MSA) data record. The main limitation effecting the quality of this release was non-removed clouds by the incorporated cloud screening procedure that caused too high albedo values, in particular for regions with permanent cloud coverage. For the generation of Release 2, the MSA algorithm has been replaced with the Geostationary Surface Albedo (GSA) one, able to process imagery from any geostationary imager. The GSA algorithm exploits a new, improved, cloud mask allowing better cloud screening, and thus fixing the major limitation of Release 1. Furthermore, the data record has an extended temporal and spatial coverage compared to the previous release. Both Black-Sky Albedo (BSA) and White-Sky Albedo (WSA) are estimated, together with their associated uncertainties. A direct comparison between Release 1 and Release 2 clearly shows that the quality of the retrieval improved significantly with the new cloud mask. For Release 2 the decadal trend is less than 1% over stable desert sites. The validation against Moderate Resolution Imaging Spectroradiometer (MODIS) and the Southern African Regional Science Initiative (SAFARI) surface albedo shows a good agreement for bright desert sites and a slightly worse agreement for urban and rain forest locations. In conclusion, compared with MSA Release 1, GSA Release 2 provides the users with a significantly more longer time range, reliable and robust surface albedo data record.

scholarly journals Denitrifying pathways dominate nitrous oxide emissions from managed grassland during drought and rewetting

2021 ◽  
Vol 7 (6) ◽  
pp. eabb7118
Author(s):  
E. Harris ◽  
E. Diaz-Pines ◽  
E. Stoll ◽  
M. Schloter ◽  
S. Schulz ◽  
...  
Keyword(s):  
Growth Rate ◽  
Nitrous Oxide ◽  
N Fertilization ◽  
High Variability ◽  
Nitrous Oxide Emissions ◽  
Severe Drought ◽  
Total N ◽  
The Past ◽  
Precipitation Changes ◽  
Isotopic Measurements

Nitrous oxide is a powerful greenhouse gas whose atmospheric growth rate has accelerated over the past decade. Most anthropogenic N2O emissions result from soil N fertilization, which is converted to N2O via oxic nitrification and anoxic denitrification pathways. Drought-affected soils are expected to be well oxygenated; however, using high-resolution isotopic measurements, we found that denitrifying pathways dominated N2O emissions during a severe drought applied to managed grassland. This was due to a reversible, drought-induced enrichment in nitrogen-bearing organic matter on soil microaggregates and suggested a strong role for chemo- or codenitrification. Throughout rewetting, denitrification dominated emissions, despite high variability in fluxes. Total N2O flux and denitrification contribution were significantly higher during rewetting than for control plots at the same soil moisture range. The observed feedbacks between precipitation changes induced by climate change and N2O emission pathways are sufficient to account for the accelerating N2O growth rate observed over the past decade.

scholarly journals On the Seasonality of the Snow Optical Behaviour at Ny Ålesund (Svalbard Islands, Norway)

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 112
Author(s):  
Roberto Salzano ◽  
Christian Lanconelli ◽  
Giulio Esposito ◽  
Marco Giusto ◽  
Mauro Montagnoli ◽  
...  
Keyword(s):  
Climate Change ◽  
Continuous Monitoring ◽  
Surface Albedo ◽  
Narrow Band ◽  
Full Range ◽  
Remotely Sensed Data ◽  
Summer Period ◽  
Significant Information ◽  
Melting Period ◽  
Optical Behavior

Polar areas are the most sensitive targets of climate change. From this perspective, the continuous monitoring of the cryosphere represents a critical need, which, now, we can only partially supply with specific satellite missions. The integration between remote-sensed multi-spectral images and field data is crucial to validate retrieval algorithms and climatological models. The optical behavior of snow, at different wavelengths, provides significant information about the microphysical characteristics of the surface in addition to the spatial distribution of snow/ice covers. This work presents the unmanned apparatus installed at Ny Ålesund (Svalbard) that provides continuous spectral surface albedo. A narrow band device was compared to a full-range system, to remotely sensed data during the 2015 spring/summer period at the Amundsen-Nobile Climate Change Tower. The system was integrated with a camera aimed to acquire sky and ground images. The results confirmed the possibility of making continuous observations of the snow surface and highlighted the opportunity to monitor the spectral variations of snowed surfaces during the melting period.

scholarly journals Consequences of the 2019 Greenland Ice Sheet Melt Episode on Albedo

2021 ◽  
Vol 13 (2) ◽  
pp. 227
Author(s):  
Arthur Elmes ◽  
Charlotte Levy ◽  
Angela Erb ◽  
Dorothy K. Hall ◽  
Ted A. Scambos ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Surface Albedo ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Energy Budget ◽  
Landsat 8 ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Seasonal Snow Cover

In mid-June 2019, the Greenland ice sheet (GrIS) experienced an extreme early-season melt event. This, coupled with an earlier-than-average melt onset and low prior winter snowfall over western Greenland, led to a rapid decrease in surface albedo and greater solar energy absorption over the melt season. The 2019 melt season resulted in significantly more melt than other recent years, even compared to exceptional melt years previously identified in the moderate-resolution imaging spectroradiometer (MODIS) record. The increased solar radiation absorbance in 2019 warmed the surface and increased the rate of meltwater production. We use two decades of satellite-derived albedo from the MODIS MCD43 record to show a significant and extended decrease in albedo in Greenland during 2019. This decrease, early in the melt season and continuing during peak summer insolation, caused increased radiative forcing of the ice sheet of 2.33 Wm−2 for 2019. Radiative forcing is strongly influenced by the dramatic seasonal differences in surface albedo experienced by any location experiencing persistent and seasonal snow-cover. We also illustrate the utility of the newly developed Landsat-8 albedo product for better capturing the detailed spatial heterogeneity of the landscape, leading to a more refined representation of the surface energy budget. While the MCD43 data accurately capture the albedo for a given 500 m pixel, the higher spatial resolution 30 m Landsat-8 albedos more fully represent the detailed landscape variations.

scholarly journals A Spatial and Temporal Assessment of Vegetation Greening and Precipitation Changes for Monitoring Vegetation Dynamics in Climate Zones over Africa

2021 ◽  
Vol 10 (3) ◽  
pp. 129
Author(s):  
Vincent Nzabarinda ◽  
Anming Bao ◽  
Wenqiang Xu ◽  
Solange Uwamahoro ◽  
Madeleine Udahogora ◽  
...  
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Forest Type ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Plant Health ◽  
Tree Cover ◽  
Climatic Zones ◽  
Dramatic Decline ◽  
Precipitation Changes

Vegetation is vital, and its greening depends on access to water. Thus, precipitation has a considerable influence on the health and condition of vegetation and its amount and timing depend on the climatic zone. Therefore, it is extremely important to monitor the state of vegetation according to the movements of precipitation in climatic zones. Although a lot of research has been conducted, most of it has not paid much attention to climatic zones in the study of plant health and precipitation. Thus, this paper aims to study the plant health in five African climatic zones. The linear regression model, the persistence index (PI), and the Pearson correlation coefficients were applied for the third generation Normalized Difference Vegetation Index (NDVI3g), with Climate Hazard Group infrared precipitation and Climate Change Initiative Land Cover for 34 years (1982 to 2015). This involves identifying plants in danger of extinction or in dramatic decline and the relationship between vegetation and rainfall by climate zone. The forest type classified as tree cover, broadleaved, deciduous, closed to open (>15%) has been degraded to 74% of its initial total area. The results also revealed that, during the study period, the vegetation of the tropical, polar, and warm temperate zones showed a higher rate of strong improvement. Although arid and boreal zones show a low rate of strong improvement, they are those that experience a low percentage of strong degradation. The continental vegetation is drastically decreasing, especially forests, and in areas with low vegetation, compared to more vegetated areas, there is more emphasis on the conservation of existing plants. The variability in precipitation is excessively hard to tolerate for more types of vegetation.

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