High-Resolution Climatic Analysis and Southwest Biogeography

Science ◽  
1986 ◽  
Vol 232 (4746) ◽  
pp. 27-34 ◽  
Author(s):  
RONALD P. NEILSON
Keyword(s):  
Large Scale ◽  
Ecological Monitoring ◽  
American Southwest ◽  
Photosynthetic Pathway ◽  
Desert Shrubs ◽  
The North ◽  
High Frequency Variability ◽  
Effect Relation ◽  
Effect Hypothesis

Meteorologists and climatologists have produced significant new data on the fluid dynamics of the atmosphere, thus allowing biologists to examine more closely the cause-effect relation between the large-scale structure of the atmosphere and the dominant patterns of global biogeography. The inability to characterize the high-frequency variability of the weather has constrained such efforts. A method that allows year-to-year patterns of weather variability to be characterized in the contexts of global warming and cooling trends is applied in a combined analysis of long-term monthly weather records and data from an ecological monitoring project in southern New Mexico. The analysis suggests a cause-effect hypothesis of recent desertification in the North American Southwest. The links between the atmosphere and the biosphere are based on the fundamentally different responses to specific weather regimes of semidesert grasses with a C4photosynthetic pathway and desert shrubs with a C3photosynthetic pathway. The hypothesis appears to be of sufficient generality to explain the complex, but well-documented, floristic changes that have occurred in the same region since the last glacial maximum.

Results of an International Plankton Investigation on the River Rhine

1994 ◽  
Vol 29 (3) ◽  
pp. 9-19 ◽  
Author(s):  
D. (G.) M. J. Tubbing ◽  
W. Admiraal ◽  
D. Backhaus ◽  
G. Friedrich ◽  
E. D. de Ruyter van Steveninck ◽  
...  
Keyword(s):  
Dreissena Polymorpha ◽  
Large Scale ◽  
Ecological Monitoring ◽  
Lake Constance ◽  
River Rhine ◽  
The North ◽  
Action Programme ◽  
Long Term Trends ◽  
Sparse Population

Quantitative plankton observations have been carried out in the River Rhine from Lake Constance to the North Sea as part of an ecological monitoring programme, initiated to provide a baseline for evaluating measures taken under the “Rhine Action Programme”. The phyto- and Zooplankton monitoring, carried out in 1990 is the first concerted programme covering the 1000 km long reach of the river below Lake Constance. Seasonal observations at 20 fixed stations along the river were carried out by different institutes; this required calibration of methods. In the upper Rhine the sparse population of phyto-plankton (< 5 µg chlorophyll-a l-1) was dominated by various groups of algae, i.e. Cryptop-hyceae, Bacillariophyceae, Chlorophyceae and Cyanophyceae. Downstream, the phyto-plankton density increased gradually, while Bacillariophyceae tended to dominate. The high densities found in the lower R. Rhine represented only a few species of centric Bacillariophyceae and Chlorophyceae. The dense blooms of phytoplankton in the lower R. Rhine are triggered by the input of phytoplankton from the upper reaches and tributaries, and are stimulated by large inputs of nutrients. These blooms are accompanied by blooms of Zooplankton, especially rotifers, Dreissena polymorpha larvae and, in the lower Rhine, nauplii larvae. The species composition and biomass of plankton in the R. Rhine vary strongly during the year but also between years, as indicated for the period 1980-1990. However, the information at the species level needs further elaboration to allow interpretation of long-term trends. Notably, the input by tributaries should be included. To assess these long-term trends we recommend supplementing the large-scale biological inventory, as planned for the years 1995 and 2000, with plankton observations in the years between and investigating the relationship between the benthic and pelagic communities of the river.

scholarly journals Past megadroughts in central Europe were longer, more severe and less warm than modern droughts

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
M. Ionita ◽  
M. Dima ◽  
V. Nagavciuc ◽  
P. Scholz ◽  
G. Lohmann
Keyword(s):  
Central Europe ◽  
North Atlantic Ocean ◽  
Explosive Volcanism ◽  
American Southwest ◽  
The North ◽  
European Climate ◽  
Blocking Activity ◽  
Meteorological Observations ◽  
Dalton Minimum

AbstractMegadroughts are notable manifestations of the American Southwest, but not so much of the European climate. By using long-term hydrological and meteorological observations, as well as paleoclimate reconstructions, here we show that central Europe has experienced much longer and severe droughts during the Spörer Minimum (~AD 1400–1480) and Dalton Minimum (~AD 1770–1840), than the ones observed during the 21st century. These two megadroughts appear to be linked with a cold state of the North Atlantic Ocean and enhanced winter atmospheric blocking activity over the British Isles and western part of Europe, concurrent with reduced solar forcing and explosive volcanism. Moreover, we show that the recent drought events (e.g., 2003, 2015, and 2018), are within the range of natural variability and they are not unprecedented over the last millennium.

Landscape development in western and central Dronning Maud Land, East Antarctica

2001 ◽  
Vol 13 (3) ◽  
pp. 302-311 ◽  
Author(s):  
Jens-Ove Näslund
Keyword(s):  
Large Scale ◽  
High Elevation ◽  
Continental Margins ◽  
Landscape Development ◽  
Ice Streams ◽  
The North ◽  
Ice Stream ◽  
Dronning Maud Land ◽  
Break Up

Large-scale bedrock morphology and relief of two key areas, the Jutulsessen Nunatak and the Jutulstraumen ice stream are used to discuss glascial history and landscape development in western and central Dronning Maud Land, Antarctica. Two main landform components were identified: well-defined summit plateau surfaces and a typical alpine glacial landscape. The flat, high-elevation plateau surfaces previously were part of one or several continuous regional planation surfaces. In western Dronning Maud Land, overlying cover rocks of late Palaeozoic age show that the planation surface(s) existed in the early Permian, prior to the break-up of Gondwana. A well-develoment escarpment, a mega landform typical for passive continental margins, bounds the palaeosurface remnants to the north for a distance of at least 700 km. The Cenozoic glacial landscape, incised in the palaeosurface and escarpment, is exemplified by Jutulsessen Nunatak, where a c. 1.2 km deep glacial valley system is developed. However, the prominent Penck-Jutul Trough represents some of the deepest dissection of the palaeosurface. This originally tectonic feature is today occupied by the Jutulstraumen ice stream. New topographic data show that the bed of the Penck-Jutul Trough is situated 1.9±1.1 km below sea level, and that the total landscape relief is at least 4.2 km. Today's relief is a result of several processes, including tectonic faulting, subaerial weathering, fluvial erosion, and glacial erosion. It is probable that erosion by ice streams has deepened the tectonic troughs of Dronning Maud Land since the onset of ice sheet glaciation in the Oligocene, and continues today. An attempt is made to identify major events in the long-term landscape development of Dronning Maud Land, since the break-up of the Gondwana continent.

scholarly journals Climate impacts on multidecadal <i>p</i>CO<sub>2</sub> variability in the North Atlantic: 1948–2009

2015 ◽  
Vol 12 (17) ◽  
pp. 15223-15244
Author(s):  
M. L. Breeden ◽  
G. A. McKinley
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Atlantic Multidecadal Oscillation ◽  
Climate Impacts ◽  
Co2 Uptake ◽  
Subpolar Gyre ◽  
The North ◽  
The North Atlantic

Abstract. The North Atlantic is the most intense region of ocean CO2 uptake. Here, we investigate multidecadal timescale variability of the partial pressure CO2 (pCO2) that is due to the natural carbon cycle using a regional model forced with realistic climate and pre-industrial atmospheric pCO2 for 1948–2009. Large-scale patterns of natural pCO2 variability are primarily associated with basin-averaged sea surface temperature (SST) that, in turn, is composed of two parts: the Atlantic Multidecadal Oscillation (AMO) and a long-term positive SST trend. The North Atlantic Oscillation (NAO) drives a secondary mode of variability. For the primary mode, positive AMO and the SST trend modify pCO2 with different mechanisms and spatial patterns. Warming with the positive AMO increases subpolar gyre pCO2, but there is also a significant reduction of dissolved inorganic carbon (DIC) due primarily to reduced vertical mixing. The net impact of positive AMO is to reduce pCO2 in the subpolar gyre. Through direct impacts on SST, the net impacts of positive AMO is to increase pCO2 in the subtropical gyre. From 1980 to present, long-term SST warming has amplified AMO impacts on pCO2.

scholarly journals 'The worst disaster suffered by the people of Scotland in recorded history': climate change, dearth and pathogens in the long 14th century

2015 ◽  
Vol 144 ◽  
pp. 223-244
Author(s):  
Richard Oram
Keyword(s):  
Cultural Change ◽  
Large Scale ◽  
Environmental Data ◽  
Historical Discourse ◽  
Proxy Records ◽  
The North ◽  
Political Upheaval ◽  
The People ◽  
Large Scale Change

Informing historical and archaeological discourse with environmental data culled from documentary and climate proxy records is transforming understanding of political, social economic and cultural change across the North Atlantic and European Atlantic regions generally. Limited record evidence and region-specific proxy data has hindered engagement by historians of medieval Scotland with the exploration of environmental factors as motors for long term and large scale change and adoption of the interdisciplinary methodologies involved in their use. This paper seeks to provide an overview of the potential for such data and methodologies in providing context for the well-rehearsed narratives of political upheaval and socio-economic realignment that have characterised much past Scottish historical discourse.

scholarly journals Survey of the terrestrial habitats and vegetation of Shetland, 1974 – a framework for long-term ecological monitoring

2016 ◽  
Vol 8 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Claire M. Wood ◽  
Robert G. H. Bunce
Keyword(s):  
Natural Environment ◽  
Large Scale ◽  
Oil Industry ◽  
Ecological Monitoring ◽  
Robust Methods ◽  
Ecological Changes ◽  
Terrestrial Habitats ◽  
Environmental Monitoring Programme

Abstract. A survey of the natural environment was undertaken in Shetland in 1974, after concern was expressed that large-scale development from the new oil industry could threaten the natural features of the islands. A framework was constructed by the Institute of Terrestrial Ecology on which to select samples for the survey. The vegetation and habitat data that were collected, along with the sampling framework, have recently been made public via the following doi:10.5285/06fc0b8c-cc4a-4ea8-b4be-f8bd7ee25342 (Terrestrial habitat, vegetation and soil data from Shetland, 1974) and doi:10.5285/f1b3179e-b446-473d-a5fb-4166668da146 (Land Classification of Shetland 1974). In addition to providing valuable information about the state of the natural environment of Shetland, the repeatable and statistically robust methods developed in the survey were used to underpin the Countryside Survey, Great Britain's national long-term integrated environmental monitoring programme. The demonstration of the effectiveness of the methodology indicates that a repeat of the Shetland survey would yield statistics about ecological changes in the islands, such as those arising from the impacts of the oil industry, a range of socio-economic impacts, and perhaps climate change. Currently no such figures are available, although there is much information on the sociological impacts, as well as changes in agriculture.

scholarly journals Hydro-businesses: National and Global Demands on the São Francisco River Basin Environment of Brazil

2010 ◽  
Vol 55 (S18) ◽  
pp. 203-233
Author(s):  
Lucigleide Nery Nascimento ◽  
Mimi Larsen Becker
Keyword(s):  
Large Scale ◽  
The United States ◽  
Economic Approach ◽  
Hydro Power ◽  
Federal Policies ◽  
Sao Francisco River ◽  
North East ◽  
The North ◽  
São Francisco River

SummaryThe São Francisco River provided very obvious, close-by forms of sustenance for local communities. Beginning in the mid-1950s, the river became the place for large hydro-electric facilities, large-scale flooding, and population resettlement. A decade later, the federal government began working on pilot irrigation projects that would lead to areas described today as the Brazilian California. Hydro-power for Brazilian cities such as Recife and Salvador and irrigation for grapes and mangoes destined for the United States and Europe are among the eco-system services this river supplies. The purpose of federal policies for the north-east went beyond mitigation of the consequences of droughts, the hydraulic approach, and started to follow an economic approach based upon development; as a consequence, river and user came to be distant from one another. The two major intensive uses of the river, electricity and irrigation, threaten the long-term sustainability of this system.

scholarly journals Influence of multidecadal variability on high and low flows: the case of the Seine basin

2020 ◽  
Vol 24 (4) ◽  
pp. 1611-1631
Author(s):  
Rémy Bonnet ◽  
Julien Boé ◽  
Florence Habets
Keyword(s):  
Large Scale ◽  
Hydrological Modeling ◽  
Spring Precipitation ◽  
Seine River ◽  
River Flows ◽  
Multidecadal Variability ◽  
Low Flows ◽  
The North ◽  
Hydrological Variability

Abstract. The multidecadal hydroclimate variations of the Seine basin since the 1850s are investigated. Given the scarcity of long-term hydrological observations, a hydrometeorological reconstruction is developed based on hydrological modeling and a method that combines the results of a downscaled long-term atmospheric reanalysis and local observations of precipitation and temperature. This method improves previous attempts and provides a realistic representation of daily and monthly river flows. This new hydrometeorological reconstruction, available over more than 150 years while maintaining fine spatial and temporal resolutions, provides a tool to improve our understanding of the multidecadal hydrological variability in the Seine basin, as well as its influence on high and low flows. This long-term reconstruction allows analysis of the strong multidecadal variations of the Seine river flows. The main hydrological mechanisms at the origin of these variations are highlighted. Spring precipitation plays a central role by directly influencing not only the multidecadal variability in spring flows but also soil moisture and groundwater recharge, which then regulate summer river flows. These multidecadal hydroclimate variations in the Seine basin are driven by anomalies in large-scale atmospheric circulation, which themselves appear to be influenced by sea surface temperature anomalies over the North Atlantic and the North Pacific. The multidecadal hydroclimate variations also influence high and low flows over the last 150 years. The analysis of two particularly severe historical droughts, the 1921 and the 1949 events, illustrates how long-term hydroclimate variations may impact short-term drought events, particularly through groundwater–river exchanges. The multidecadal hydroclimate variations described in this study, probably of internal origin, could play an important role in the evolution of water resources in the Seine basin in the coming decades. It is therefore essential to take the associated uncertainties into account in future projections.

scholarly journals The long-term variability of extreme sea levels in the German Bight

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 651-668 ◽  
Author(s):  
Andreas Lang ◽  
Uwe Mikolajewicz
Keyword(s):  
Sea Level ◽  
German Bight ◽  
Large Scale ◽  
Internal Variability ◽  
Climate System ◽  
System Model ◽  
Tide Gauge Record ◽  
Sea Levels ◽  
The North

Abstract. Extreme high sea levels (ESLs) caused by storm floods constitute a major hazard for coastal regions. We here quantify their long-term variability in the southern German Bight using simulations covering the last 1000 years. To this end, global earth system model simulations from the PMIP3 past1000 project are dynamically scaled down with a regionally coupled climate system model focusing on the North Sea. This approach provides an unprecedented long high-resolution data record that can extend the knowledge of ESL variability based on observations, and allows for the identification of associated large-scale forcing mechanisms in the climate system. While the statistics of simulated ESLs compare well with observations from the tide gauge record at Cuxhaven, we find that simulated ESLs show large variations on interannual to centennial timescales without preferred oscillation periods. As a result of this high internal variability, ESL variations appear to a large extent decoupled from those of the background sea level, and mask any potential signals from solar or volcanic forcing. Comparison with large-scale climate variability shows that periods of high ESL are associated with a sea level pressure dipole between northeastern Scandinavia and the Gulf of Biscay. While this large-scale circulation regime applies to enhanced ESL in the wider region, it differs from the North Atlantic Oscillation pattern that has often been linked to periods of elevated background sea level. The high internal variability with large multidecadal to centennial variations emphasizes the inherent uncertainties related to traditional extreme value estimates based on short data subsets, which fail to account for such long-term variations. We conclude that ESL variations as well as existing estimates of future changes are likely to be dominated by internal variability rather than climate change signals. Thus, larger ensemble simulations will be required to assess future flood risks.

scholarly journals Analysis of Long-Term Moon-Based Observation Characteristics for Arctic and Antarctic

2019 ◽  
Vol 11 (23) ◽  
pp. 2805 ◽  
Author(s):  
Yue Sui ◽  
Huadong Guo ◽  
Guang Liu ◽  
Yuanzhen Ren
Keyword(s):  
Global Climate Change ◽  
Large Scale ◽  
Global Climate ◽  
Earth Observation ◽  
Polar Regions ◽  
The Moon ◽  
The North ◽  
The Earth ◽  
The Antarctic

The Antarctic and Arctic have always been critical areas of earth science research and are sensitive to global climate change. Global climate change exhibits diversity characteristics on both temporal and spatial scales. Since the Moon-based earth observation platform could provide large-scale, multi-angle, and long-term measurements complementary to the satellite-based Earth observation data, it is necessary to study the observation characteristics of this new platform. With deepening understanding of Moon-based observations, we have seen its good observation ability in the middle and low latitudes of the Earth’s surface, but for polar regions, we need to further study the observation characteristics of this platform. Based on the above objectives, we used the Moon-based Earth observation geometric model to quantify the geometric relationship between the Sun, Moon, and Earth. Assuming the sensor is at the center of the nearside of the Moon, the coverage characteristics of the earth feature points are counted. The observation intervals, access frequency, and the angle information of each point during 100 years were obtained, and the variation rule was analyzed. The research showed that the lunar platform could carry out ideal observations for the polar regions. For the North and South poles, a continuous observation duration of 14.5 days could be obtained, and as the latitude decreased, the duration time was reduced to less than one day at the latitude of 65° in each hemisphere. The dominant observation time of the North Pole is concentrated from mid-March to mid-September, and for the South Pole, it is the rest of the year, and as the latitude decreases, it extends outward from both sides. The annual coverage time and frequency will change with the relationship between the Moon and the Earth. This study also proves that the Moon-based observation has multi-angle observation advantages for the Arctic and the Antarctic areas, which can help better understand large-scale geoscientific phenomena. The above findings indicate that the Moon-based observation can be applied as a new type of remote sensing technology to the observation field of the Earth’s polar regions.

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