Long-term MF radar observations of solar tides in the low-latitude mesosphere: Interannual variability and comparisons with the GSWM

How do weather shocks influence human mobility and poverty, and how will long-term climate change affect future migration over the course of the 21st century? These questions have gained unprecedented attention in public debates as global warming is already having severe impacts around the world, and prospects for the coming decades get worse. Low-latitude countries in general, and their agricultural areas in particular, have contributed the least to climate change but are the most adversely affected. The effect on people's voluntary and forced displacements is of major concern for both developed and developing countries. On 18 October 2019, Agence Française de Développement (AFD) and Luxembourg Institute of Socio-Economic Research (LISER) organized a workshop on Climate Migration with the aim of uncovering the mechanisms through which fast-onset variables (such as weather anomalies, storms, hurricanes, torrential rains, floods, landslides, etc.) and slow-onset variables (such as temperature trends, desertification, rising sea level, coastal erosion, etc.) influence both people's incentives to move and mobility constraints. This special issue gathers five papers prepared for this workshop, which shed light on (or predict) the effect of extreme weather shocks and long-term climate change on human mobility, and stress the implications for the development community.

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Vegetation and microbes interact to preserve carbon in many wooded peatlands

Communications Earth & Environment ◽

10.1038/s43247-021-00136-4 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Hongjun Wang ◽

Jianqing Tian ◽

Huai Chen ◽

Mengchi Ho ◽

Rytas Vilgalys ◽

...

Keyword(s):

Microbial Composition ◽

Ecological Traits ◽

Low Latitude ◽

Carbon Decomposition ◽

Positive Effects ◽

Recalcitrant Carbon ◽

Effects Of Temperature ◽

Abiotic Controls ◽

Slow Growing

AbstractPeatlands have persisted as massive carbon sinks over millennia, even during past periods of climate change. The commonly accepted theory of abiotic controls (mainly anoxia and low temperature) over carbon decomposition cannot fully explain how vast low-latitude shrub/tree dominated (wooded) peatlands consistently accrete peat under warm and seasonally unsaturated conditions. Here we show, by comparing the composition and ecological traits of microbes between Sphagnum- and shrub-dominated peatlands, that slow-growing microbes decisively dominate the studied shrub-dominated peatlands, concomitant with plant-induced increases in highly recalcitrant carbon and phenolics. The slow-growing microbes metabolize organic matter thirty times slower than the fast-growing microbes that dominate our Sphagnum-dominated site. We suggest that the high-phenolic shrub/tree induced shifts in microbial composition may compensate for positive effects of temperature and/or drought on metabolism over time in peatlands. This biotic self-sustaining process that modulates abiotic controls on carbon cycling may improve projections of long-term, climate-carbon feedbacks in peatlands.

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HF Doppler radar observations of low-latitude spread F

Radio Science ◽

10.1029/2007rs003777 ◽

2009 ◽

Vol 44 (3) ◽

pp. n/a-n/a ◽

Cited By ~ 2

Author(s):

C. R. Reddi ◽

M. S. S. R. K. N. Sarma ◽

K. Niranjan

Keyword(s):

Doppler Radar ◽

Low Latitude ◽

Radar Observations ◽

Spread F

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Pleistocene–Holocene environmental change in the Canary Archipelago as inferred from the stable isotope composition of land snail shells

Quaternary Research ◽

10.1016/j.yqres.2010.11.004 ◽

2011 ◽

Vol 75 (3) ◽

pp. 658-669 ◽

Cited By ~ 29

Author(s):

Yurena Yanes ◽

Crayton J. Yapp ◽

Miguel Ibáñez ◽

María R. Alonso ◽

Julio De-la-Nuez ◽

...

Keyword(s):

Environmental Change ◽

Canary Islands ◽

Environmental Changes ◽

Isotope Composition ◽

Moving Average ◽

Land Snail ◽

Balance Model ◽

Low Latitude ◽

The Times

AbstractThe isotopic composition of land snail shells was analyzed to investigate environmental changes in the eastern Canary Islands (28–29°N) over the last ~ 50 ka. Shell δ13C values range from −8.9‰ to 3.8‰. At various times during the glacial interval (~ 15 to ~ 50 ka), moving average shell δ13C values were 3‰ higher than today, suggesting a larger proportion of C4 plants at those periods. Shell δ18O values range from −1.9‰ to 4.5‰, with moving average δ18O values exhibiting a noisy but long-term increase from 0.1‰ at ~ 50 ka to 1.6–1.8‰ during the LGM (~ 15–22 ka). Subsequently, the moving average δ18O values range from 0.0‰ at ~ 12 ka to 0.9‰ at present. Calculations using a published snail flux balance model for δ18O, constrained by regional temperatures and ocean δ18O values, suggest that relative humidity at the times of snail activity fluctuated but exhibited a long-term decline over the last ~ 50 ka, eventually resulting in the current semiarid conditions of the eastern Canary Islands (consistent with the aridification process in the nearby Sahara). Thus, low-latitude oceanic island land snail shells may be isotopic archives of glacial to interglacial and tropical/subtropical environmental change.

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NLC and the background atmosphere above ALOMAR

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-5701-2011 ◽

2011 ◽

Vol 11 (12) ◽

pp. 5701-5717 ◽

Cited By ~ 41

Author(s):

J. Fiedler ◽

G. Baumgarten ◽

U. Berger ◽

P. Hoffmann ◽

N. Kaifler ◽

...

Keyword(s):

Diurnal Cycle ◽

Middle Atmosphere ◽

Thermal State ◽

Atmospheric Tides ◽

Data Set ◽

Ice Particles ◽

Cloud Water Content ◽

Radar Measurements ◽

Mf Radar

Abstract. Noctilucent clouds (NLC) have been measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69° N, 16° E). From 1997 to 2010 NLC were detected during more than 1850 h on 440 different days. Colocated MF-radar measurements and calculations with the Leibniz-Institute Middle Atmosphere (LIMA-) model are used to characterize the background atmosphere. Temperatures as well as horizontal winds at 83 km altitude show distinct differences during NLC observations compared to when NLC are absent. The seasonally averaged temperature is lower and the winds are stronger westward when NLC are detected. The wind separation is a robust feature as it shows up in measurements as well as in model results and it is consistent with the current understanding that lower temperatures support the existence of ice particles. For the whole 14-year data set there is no statistically significant relation between NLC occurrence and solar Lyman-α radiation. On the other hand NLC occurrence and temperatures at 83 km show a significant anti-correlation, which suggests that the thermal state plays a major role for the existence of ice particles and dominates the pure Lyman-α influence on water vapor during certain years. We find the seasonal mean NLC altitudes to be correlated to both Lyman-α radiation and temperature. NLC above ALOMAR are strongly influenced by atmospheric tides. The cloud water content varies by a factor of 2.8 over the diurnal cycle. Diurnal and semidiurnal amplitudes and phases show some pronounced year-to-year variations. In general, amplitudes as well as phases vary in a different manner. Amplitudes change by a factor of more than 3 and phases vary by up to 7 h. Such variability could impact long-term NLC observations which do not cover the full diurnal cycle.

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Interhemispheric differences of mesosphere/lower thermosphere winds and tides investigated from three whole atmosphere models and meteor radar observations

10.5194/acp-2021-142 ◽

2021 ◽

Author(s):

Gunter Stober ◽

Ales Kuchar ◽

Dimitry Pokhotelov ◽

Huixin Liu ◽

Han-Li Liu ◽

...

Keyword(s):

General Circulation ◽

Climate Models ◽

Climate Model ◽

Lower Thermosphere ◽

Winter Season ◽

General Circulation Models ◽

Meteor Radar ◽

Radar Observations ◽

Seasonal Characteristics

Abstract. Long-term and continuous observations of mesospheric/lower thermospheric winds are rare, but they are important to investigate climatological changes at these altitudes on time scales of several years, covering a solar cycle and longer. Such long time series are a natural heritage of the mesosphere/lower thermosphere climate, and they are valuable to compare climate models or long term runs of general circulation models (GCMs). Here we present a climatological comparison of wind observations from six meteor radars at two conjugate latitudes to validate the corresponding mean winds and atmospheric diurnal and semidiurnal tides from three GCMs, namely Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA), Whole Atmosphere Community Climate Model Extension (Specified Dynamics) (WACCM-X(SD)) and Upper Atmosphere ICOsahedral Non-hydrostatic (UA-ICON) model. Our results indicate that there are interhemispheric differences in the seasonal characteristics of the diurnal and semidiurnal tide. There also are some differences in the mean wind climatologies of the models and the observations. Our results indicate that GAIA shows a reasonable agreement with the meteor radar observations during the winter season, whereas WACCM-X(SD) shows a better agreement with the radars for the hemispheric zonal summer wind reversal, which is more consistent with the meteor radar observations. The free running UA-ICON tends to show similar winds and tides compared to WACCM-X(SD).

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Geographical variability of length-age structure of the Black Sea sprat Sprattus sprattus phalericus (Risso) (Pisces: Clupeidae) and intraspecific differentiation

Marine Biological Journal ◽

10.21072/mbj.2016.01.1.03 ◽

2016 ◽

Vol 1 (1) ◽

pp. 24-35

Author(s):

G. V. Zuyev ◽

V. A. Bondarev ◽

Yu. V. Samotoi

Keyword(s):

Interannual Variability ◽

Black Sea ◽

Age Structure ◽

The Black Sea ◽

Population Parameter ◽

Intraspecific Differentiation ◽

Geographical Regions ◽

The Crimea ◽

Scientific Technical

Investigations of the Black Sea sprat intraspecific differentiation are the basis for the scientific substantiation of rational exploitation of its resource potential. This work is devoted to the study of spatial variability of length and age structure of sprat as specific population parameter reflecting its intraspecific differentiation. Our own data and materials of Scientific, Technical and Economic Committee for Fisheries (STECF) of the European Commission have been used. The first time long-term dynamics (2007–2012) and interannual variability of length and age structure of sprat in different geographical regions of the Black Sea (coastal waters of Bulgaria – Romania, Turkey and the Crimea) have been investigated. Differences of the long-term dynamics and interannual variability of length and age structure in these regions have been found. Sprat population from Bulgaria – Romania region is in better conditions (mean length 8.59 ± 0.01 cm; mean age 1.79 year), sprat population from Crimea region is in worse conditions (mean length 7.64 ± 0.01 cm; mean age 1.38 year). It has been shown that the main factor determining the interregional biological heterogeneity of sprat is the different fishery regulations. This fact disagrees with concept of united commercial sprat stock in the Black Sea.

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