Continental-Scale Analysis of Atmospheric Deposition Over North America and Europe Using the AQMEII Database

In a previous paper published in the Geological Magazine, the writer made an attempt to discuss the mechanism of earth movement on a continental scale purely from a tectonic point of view. The problem is so vast and involved that some of the vital points were hardly touched upon, partly because of lack of space and partly of literature. The arrival of the admirable works of Dr. A. du Toit and Dr. E. Krenkel has enabled the writer to deduce the mechanism of the movements of South Africa directly from its tectonic features, which process is thought to be far more reliable than the type of argument used in the previous case although the results arrived at are essentially the same. The earlier movements in North America are now seen to furnish evidence of the same type of mechanism as that which staged the later movements. An epsilon type of structure has been recognized in Eastern China, which was then described as a mere arc. The problem of the distribution of concealed coalfields in England was in the previous paper barely touched upon. It is now proposed to consider some of the critical points bearing on the problem.

Download Full-text

The History of Atmospheric Deposition of Cd, Hg, and Pb in North America: Evidence from Lake and Peat Bog Sediments

Acidic Precipitation - Advances in Environmental Science ◽

10.1007/978-1-4612-4454-7_4 ◽

1990 ◽

pp. 73-102 ◽

Cited By ~ 36

Author(s):

Stephen A. Norton ◽

Peter J. Dillon ◽

R. Douglas Evans ◽

Gregory Mierle ◽

Jeffrey S. Kahl

Keyword(s):

North America ◽

Atmospheric Deposition ◽

Peat Bog ◽

History Of

Download Full-text

Towards a Holarctic synthesis of peatland testate amoeba ecology: Development of a new continental-scale palaeohydrological transfer function for North America and comparison to European data

Quaternary Science Reviews ◽

10.1016/j.quascirev.2018.10.034 ◽

2018 ◽

Vol 201 ◽

pp. 483-500 ◽

Cited By ~ 13

Author(s):

Matthew J. Amesbury ◽

Robert K. Booth ◽

Thomas P. Roland ◽

Joan Bunbury ◽

Michael J. Clifford ◽

...

Keyword(s):

North America ◽

Transfer Function ◽

Testate Amoeba ◽

Continental Scale ◽

European Data

Download Full-text

Drought Relief and Reversal over North America from 1500 to 2016

Earth Interactions ◽

10.1175/ei-d-20-0020.1 ◽

2021 ◽

Vol 25 (1) ◽

pp. 94-107

Author(s):

M. C. A. Torbenson ◽

D. W. Stahle ◽

I. M. Howard ◽

D. J. Burnette ◽

D. Griffin ◽

...

Keyword(s):

Soil Moisture ◽

North America ◽

Land Surface ◽

Large Scale ◽

Temporal Stability ◽

Warm Season ◽

Cool Season ◽

Continental Scale ◽

The North ◽

Drought Relief

Abstract Season-to-season persistence of soil moisture drought varies across North America. Such interseasonal autocorrelation can have modest skill in forecasting future conditions several months in advance. Because robust instrumental observations of precipitation span less than 100 years, the temporal stability of the relationship between seasonal moisture anomalies is uncertain. The North American Seasonal Precipitation Atlas (NASPA) is a gridded network of separately reconstructed cool-season (December–April) and warm-season (May–July) precipitation series and offers new insights on the intra-annual changes in drought for up to 2000 years. Here, the NASPA precipitation reconstructions are rescaled to represent the long-term soil moisture balance during the cool season and 3-month-long atmospheric moisture during the warm season. These rescaled seasonal reconstructions are then used to quantify the frequency, magnitude, and spatial extent of cool-season drought that was relieved or reversed during the following summer months. The adjusted seasonal reconstructions reproduce the general patterns of large-scale drought amelioration and termination in the instrumental record during the twentieth century and are used to estimate relief and reversals for the most skillfully reconstructed past 500 years. Subcontinental-to-continental-scale reversals of cool-season drought in the following warm season have been rare, but the reconstructions display periods prior to the instrumental data of increased reversal probabilities for the mid-Atlantic region and the U.S. Southwest. Drought relief at the continental scale may arise in part from macroscale ocean–atmosphere processes, whereas the smaller-scale regional reversals may reflect land surface feedbacks and stochastic variability.

Download Full-text

Urban Environments Aid Invasion of Brown Widows (Theridiidae: Latrodectus geometricus) in North America, Constraining Regions of Overlap and Mitigating Potential Impact on Native Widows

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.757902 ◽

2021 ◽

Vol 9 ◽

Author(s):

Melissa Sadir ◽

Katharine A. Marske

Keyword(s):

North America ◽

Ecological Niche Modeling ◽

Climatic Factors ◽

Ecological Impact ◽

Niche Differentiation ◽

Urban Environments ◽

Geographic Ranges ◽

Native Communities ◽

Continental Scale ◽

Latrodectus Geometricus

Urbanization is a major cause of biotic homogenization and habitat fragmentation for native communities. However, the role of urbanization on the success of biological invasions on a continental scale has yet to be explored. Urbanization may facilitate the establishment success of invasive species by minimizing niche differentiation between native and invaded ranges. In such cases, we might expect anthropogenic variables to have stronger influence on the geographic distribution of invasive compared to native populations. In this study, we use ecological niche modeling to define the distribution of non-native brown widow spider (Latrodectus geometricus) and three native black widows (L. hespersus, L. mactans, L. variolus) in North America and gauge the importance of urbanization on the geographic ranges of widows at a continental scale. We also quantify the geographic overlap of L. geometricus with each native widow to assess potential species and regions at risk of ecological impact. Consistent with our hypothesis, we find that the distribution of L. geometricus is strongly constrained to urban environments, while native widow distributions are more strongly driven by climatic factors. These results show that urbanization plays a significant role in facilitating the success of invasion, weakening the significance of climate on the realized niche in its invaded range.

Download Full-text

Mechanisms of Seasonal Soil Moisture Drought Onset and Termination in the Southern Great Plains

Journal of Hydrometeorology ◽

10.1175/jhm-d-18-0191.1 ◽

2019 ◽

Vol 20 (4) ◽

pp. 751-771 ◽

Cited By ~ 2

Author(s):

Richard Seager ◽

Jennifer Nakamura ◽

Mingfang Ting

Keyword(s):

Soil Moisture ◽

North America ◽

Great Plains ◽

Land Surface ◽

Tropical Pacific ◽

Moisture Change ◽

Southern Plains ◽

Southern Great Plains ◽

Continental Scale ◽

Over Time

AbstractMechanisms of drought onset and termination are examined across North America with a focus on the southern Plains using data from land surface models and regional and global reanalyses for 1979–2017. Continental-scale analysis of covarying patterns reveals a tight coupling between soil moisture change over time and intervening precipitation anomalies. The southern Great Plains are a geographic center of patterns of hydrologic change. Drying is induced by atmospheric wave trains that span the Pacific and North America and place northerly flow anomalies above the southern Plains. In the southern Plains winter is least likely, and fall most likely, for drought onset and spring is least likely, and fall or summer most likely, for drought termination. Southern Plains soil moisture itself, which integrates precipitation over time, has a clear relationship to tropical Pacific sea surface temperature (SST) anomalies with cold conditions favoring dry soils. Soil moisture change, however, though clearly driven by precipitation, has a weaker relation to SSTs and a strong relation to internal atmospheric variability. Little evidence is found of connection of drought onset and termination to driving by temperature anomalies. An analysis of particular drought onsets and terminations on the seasonal time scale reveals commonalities in terms of circulation and moisture transport anomalies over the southern Plains but a variety of ways in which these are connected into the large-scale atmosphere and ocean state. Some onsets are likely to be quite predictable due to forcing by cold tropical Pacific SSTs (e.g., fall 2010). Other onsets and all terminations are likely not predictable in terms of ocean conditions.

Download Full-text

Gradients of column CO<sub>2</sub> across North America from the NOAA Global Greenhouse Gas Reference Network

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-15151-2017 ◽

2017 ◽

Vol 17 (24) ◽

pp. 15151-15165 ◽

Cited By ~ 4

Author(s):

Xin Lan ◽

Pieter Tans ◽

Colm Sweeney ◽

Arlyn Andrews ◽

Andrew Jacobson ◽

...

Keyword(s):

North America ◽

Greenhouse Gas ◽

Spatial Patterns ◽

Reference Network ◽

Spatial Gradients ◽

Continental Scale ◽

Satellite Retrievals ◽

The Impact ◽

Total Column

Abstract. This study analyzes seasonal and spatial patterns of column carbon dioxide (CO2) over North America, calculated from aircraft and tall tower measurements from the NOAA Global Greenhouse Gas Reference Network from 2004 to 2014. Consistent with expectations, gradients between the eight regions studied are larger below 2 km than above 5 km. The 11-year mean CO2 dry mole fraction (XCO2) in the column below ∼  330 hPa ( ∼  8 km above sea level) from NOAA's CO2 data assimilation model, CarbonTracker (CT2015), demonstrates good agreement with those calculated from calibrated measurements on aircraft and towers. Total column XCO2 was attained by combining modeled CO2 above 330 hPa from CT2015 with the measurements. We find large spatial gradients of total column XCO2 from June to August, with north and northeast regions having ∼  3 ppm stronger summer drawdown (peak-to-valley amplitude in seasonal cycle) than the south and southwest regions. The long-term averaged spatial gradients of total column XCO2 across North America show a smooth pattern that mainly reflects the large-scale circulation. We have conducted a CarbonTracker experiment to investigate the impact of Eurasian long-range transport. The result suggests that the large summertime Eurasian boreal flux contributes about half of the north–south column XCO2 gradient across North America. Our results confirm that continental-scale total column XCO2 gradients simulated by CarbonTracker are realistic and can be used to evaluate the credibility of some spatial patterns from satellite retrievals, such as the long-term average of growing-season spatial patterns from satellite retrievals reported for Europe which show a larger spatial difference ( ∼  6 ppm) and scattered hot spots.

Download Full-text

Impact of Initial Soil Moisture Anomalies on Subsequent Precipitation over North America in the Coupled Land–Atmosphere Model CAM3–CLM3

Journal of Hydrometeorology ◽

10.1175/jhm611.1 ◽

2007 ◽

Vol 8 (3) ◽

pp. 513-533 ◽

Cited By ~ 37

Author(s):

Yeonjoo Kim ◽

Guiling Wang

Keyword(s):

Soil Moisture ◽

North America ◽

Continental Scale ◽

Model Version ◽

Initial Soil Moisture ◽

Spatial Coverage ◽

Initial Soil ◽

Atmosphere Model ◽

Shallow Soils ◽

The Impact

Abstract To investigate the impact of anomalous soil moisture conditions on subsequent precipitation over North America, a series of numerical experiments is performed using a modified version of the Community Atmosphere Model version 3 and the Community Land Model version 3 (CAM3–CLM3). First, the mechanisms underlying the impact of spring and summer soil moisture on subsequent precipitation are examined based on simulations starting on 1 April and 1 June, respectively. How the response of precipitation to initial soil moisture anomalies depends on the characteristics of such anomalies, including the timing, magnitude, spatial coverage, and vertical depth, is then investigated. There are five main findings. First, the impact of spring soil moisture anomalies is not evident until early summer although their impact on the large-scale circulation results in slight changes in precipitation during spring. Second, precipitation increases with initial soil moisture almost linearly within a certain range of soil moisture. Beyond this range, precipitation is less responsive. Third, during the first month following the onset of summer soil moisture anomalies, the precipitation response to wet anomalies is larger in magnitude than that to dry anomalies. However, the resulting wet anomalies in precipitation quickly dissipate within a month or so, while the resulting dry anomalies in precipitation remain at a considerable magnitude for a longer period. Consistently, wet spring anomalies are likely to be ameliorated before summer, and thus have a smaller impact (in magnitude) on summer precipitation than dry spring anomalies. Fourth, soil moisture anomalies of smaller spatial coverage lead to precipitation anomalies that are smaller and less persistent, compared to anomalies at the continental scale. Finally, anomalies in shallow soil can persist long enough to influence the subsequent precipitation at the seasonal time scale. Dry anomalies in deep soils last much longer than those in shallow soils.

Download Full-text