Regional scale climate forcing of mesozooplankton dynamics in Chesapeake Bay

2006 ◽  
Vol 29 (3) ◽  
pp. 375-387 ◽  
Author(s):  
David G. Kimmel ◽  
W. David Miller ◽  
Michael R. Roman
Keyword(s):  
Chesapeake Bay ◽  
Regional Scale ◽  
Climate Forcing

scholarly journals Relative impacts of global changes and regional watershed changes on the inorganic carbon balance of the Chesapeake Bay

2020 ◽  
Author(s):  
Pierre St-Laurent ◽  
Marjorie A. M. Friedrichs ◽  
Raymond G. Najjar ◽  
Elizabeth H. Shadwick ◽  
Hanqin Tian ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Chesapeake Bay ◽  
Carbon Balance ◽  
Inorganic Carbon ◽  
Regional Scale ◽  
Nitrogen Loading ◽  
Atmospheric Co2 ◽  
Past Century ◽  
Global Changes ◽  
The Past

Abstract. The Chesapeake Bay is a large coastal-plain estuary that has experienced considerable anthropogenic change over the past century. At the regional scale, land-use change has doubled the nutrient input from rivers and led to an increase in riverine carbon and alkalinity. The Bay has also experienced global changes, including the rise of atmospheric temperature and CO2. Here we seek to understand the relative impact of these changes on the inorganic carbon balance of the Bay between the early 1900's and the early 2000's. We use a linked land-estuarine-ocean modeling system that includes both inorganic and organic carbon and nitrogen cycling. Sensitivity experiments are performed to isolate the effect of changes in: (1) atmospheric CO2, (2) temperature, (3) riverine nitrogen loading and (4) riverine carbon and alkalinity loading. Specifically, we find that over the past century global changes have increased ingassing by roughly the same amount (~30 Gg-C yr−1) as has the increased riverine loadings. While the former is due primarily to increases in atmospheric CO2, the latter results from increased net ecosystem production that enhances ingassing. Interestingly, these increases in ingassing are partially mitigated by increased temperatures and increased riverine carbon and alkalinity inputs, both of which enhance outgassing. Overall, the Bay has evolved over the century to take up more atmospheric CO2 and produce more organic carbon. These results suggest that over the past century, changes in riverine nutrient loads have played an important role in altering coastal carbon budgets, but that ongoing global changes have also substantially affected coastal carbonate chemistry.

Numerical modelling assessment of glacier surge impact on observed elevation change signals

2021 ◽  
Author(s):  
Andreas Vieli
Keyword(s):  
Large Population ◽  
Regional Scale ◽  
Mass Gain ◽  
Climate Forcing ◽  
Mass Change ◽  
Elevation Change ◽  
Elevation Changes ◽  
Glacier Surges ◽  
The Mean ◽  
The Impact

<p>Glacier surges periodically move ice masses to lower elevations and hence produce dynamic patterns of substantial thinning and thickening, but the net mass change over a typical time period of elevation change assessment of a few years to decades is not obvious.  Surging glaciers may therefore affect regional scale elevation change assessments as acquired from differencing of remotely sensed elevations, as for example for the observed Karakoram mass gain anomaly.</p><p>In this study I synthetically model glacier surges for a range of glacier sizes (slopes, thicknesses) and investigate the impact on the surface elevation change and total mass change for a typical range of surge durations, intensities and periods.</p><p>When keeping the climate forcing constant I find that the mean glacier elevation (or volume) is almost symmetric around the surge phase. Hence, when sampling elevation change over a large population of glaciers with randomly occurring surges there is little impact on the detected average elevation changes over all glaciers. The exceptions are steep glaciers which produce very short advance phases and much more extended phases of mass recovery. When sampling elevation change over a couple of years to decades, it is therefore much more likely to detect a thickening and therefore the population mean is biased to positive elevation change values.</p><p>When assessing mean elevation change on a regional scale, usually one fixed glacier outline is chosen for masking the data. However, for surging glaciers the extent can undergo large fluctuations. I therefore further assess the mean elevation change for glaciers extent masks that are varying between the maximum and minimum values of a surge. Despite a constant climate, the mean elevation change turns out to be increasingly biased towards detecting a thickening signal the further upstream the glacier extent is taken. This implies that for minimizing this thickening bias from glacier surges in assessing regional elevation change, glacier outline masks from their most extensive extents should be used.</p><p>Further modelling experiment showed that, the results are still valid when prescribing a variable climate forcing, but the surging effect is slightly subdued.  </p>

scholarly journals Evaluating the skill of high-resolution WRF-Chem simulations in describing drivers of aerosol direct climate forcing on the regional scale

2016 ◽  
Vol 16 (1) ◽  
pp. 397-416 ◽  
Author(s):  
P. Crippa ◽  
R. C. Sullivan ◽  
A. Thota ◽  
S. C. Pryor
Keyword(s):  
High Resolution ◽  
Spatial Correlation ◽  
Radiative Forcing ◽  
Regional Scale ◽  
Climate Forcing ◽  
Spatiotemporal Variability ◽  
Aerosol Loading ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Assessing the ability of global and regional models to describe aerosol optical properties is essential to reducing uncertainty in aerosol direct radiative forcing in the contemporary climate and to improving confidence in future projections. Here we evaluate the performance of high-resolution simulations conducted using the Weather Research and Forecasting model with coupled with Chemistry (WRF-Chem) in capturing spatiotemporal variability of aerosol optical depth (AOD) and the Ångström exponent (AE) by comparison with ground- and space-based remotely sensed observations. WRF-Chem is run over eastern North America at a resolution of 12 km for a representative year (2008). A systematic positive bias in simulated AOD relative to observations is found (annual mean fractional bias (MFB) is 0.15 and 0.50 relative to MODIS (MODerate resolution Imaging Spectroradiometer) and AERONET, respectively), whereas the spatial variability is well captured during most months. The spatial correlation of observed and simulated AOD shows a clear seasonal cycle with highest correlation during summer months (r = 0.5–0.7) when the aerosol loading is large and more observations are available. The model is biased towards the simulation of coarse-mode aerosols (annual MFB for AE  =  −0.10 relative to MODIS and −0.59 for AERONET), but the spatial correlation for AE with observations is 0.3–0.5 during most months, despite the fact that AE is retrieved with higher uncertainty from the remote-sensing observations. WRF-Chem also exhibits high skill in identifying areas of extreme and non-extreme aerosol loading, and its ability to correctly simulate the location and relative intensity of extreme aerosol events (i.e., AOD  >  75th percentile) varies between 30 and 70 % during winter and summer months, respectively.

scholarly journals Miocene Seep-Carbonates of the Northern Apennines (Emilia to Umbria, Italy): An Overview

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 53
Author(s):  
Stefano Conti ◽  
Claudio Argentino ◽  
Chiara Fioroni ◽  
Aura Cecilia Salocchi ◽  
Daniela Fontana
Keyword(s):  
Regional Scale ◽  
Field Research ◽  
Northern Apennines ◽  
Climate Forcing ◽  
Continental Margins ◽  
Accretionary Wedge ◽  
Geological Processes ◽  
Oxygen Stable Isotopes ◽  
Active Continental Margins ◽  
Seep Carbonate

The natural emission of methane-rich fluids from the seafloor, known as cold seepage, is a widespread process at modern continental margins. The studies on present-day cold seepages provide high-resolution datasets regarding the fluid plumbing system, biogeochemical processes in the sediment, seafloor seepage distribution and ecosystems. However, the long-term (hundreds of thousands to millions of years) evolution of cold seepage remains elusive. The identification and study of outcrop analogous now exposed on land represent a valuable method for better understanding the effects of geological processes and climate forcing on the development of cold seepage systems. Here, we provide an overview on Miocene seep-carbonate deposits of the northern Apennines (from Emilia to the Umbria-Marchean sector, Italy), based on decades of field research integrated with detailed sedimentological and geochemical investigations. We report a total of 13 seep-carbonate outcrops, which formed in three different structural settings of the paleo-accretionary wedge corresponding to wedge-top basins, outer slope and intrabasinal highs at the deformational front. We discuss the recurring lithostratigraphic occurrence of seep deposits and the main compositional features (carbonate facies, carbon and oxygen stable isotopes) in order to interpret the seepage dynamics, duration and infer the contribution of methane-rich fluids released by paleo-gas hydrates. The datasets presented in this study represent a valuable complete record of cold seepage spanning ~12 Myr, that can be used to better understand factors controlling the regional-scale spatial and temporal evolution of cold seepage systems at modern active continental margins.

scholarly journals Regional scale characteristics of the seasonal cycle of chlorophyll in the Southern Ocean

2011 ◽  
Vol 8 (3) ◽  
pp. 4763-4804 ◽  
Author(s):  
S. J. Thomalla ◽  
N. Fauchereau ◽  
S. Swart ◽  
P. M. S. Monteiro
Keyword(s):  
Southern Ocean ◽  
Phytoplankton Biomass ◽  
Seasonal Cycle ◽  
Phase Locking ◽  
Regional Scale ◽  
Climate Forcing ◽  
Climate Trends ◽  
Subtropical Zone ◽  
Regional Characteristics ◽  
Scale Characteristics

Abstract. The seasonal cycle is the mode that couples climate forcing to ecosystem production. A better understanding of the regional characteristics of the seasonal cycle addresses an important gap in our understanding of the sensitivity of the biological pump to climate change. The regional characteristics of the seasonal cycle of phytoplankton biomass in the Southern Ocean were examined in terms of the timing of the bloom initiation, its amplitude, regional scale variability and the importance of the climatological seasonal cycle in explaining the overall variance. The study highlighted important differences between the spatial distribution of satellite observed phytoplankton biomass and the more dynamically linked characteristics of the seasonal cycle. The seasonal cycle was consequently defined into four broad zonal regions; the subtropical zone (STZ), the transition zone (TZ), the Antarctic circumpolar zone (ACZ) and the marginal ice zone (MIZ). Defining the Southern Ocean according to the characteristics of its seasonal cycle provides a more dynamic understanding of ocean productivity based on underlying physical drivers rather than climatological biomass. The response of the biology to the underlying physics of the different seasonal zones resulted in an additional classification of four regions based on the extent of interannual seasonal phase locking and the amplitude of the integrated seasonal biomass. This characterisation contributes to an improved understanding of regional sensitivity to climate forcing potentially allowing more robust predictions of long term climate trends.

scholarly journals Climate forcing of the spring bloom in Chesapeake Bay

2007 ◽  
Vol 331 ◽  
pp. 11-22 ◽  
Author(s):  
WD Miller ◽  
LW Harding Jr
Keyword(s):  
Chesapeake Bay ◽  
Spring Bloom ◽  
Climate Forcing

Climate Forcing and Salinity Variability in Chesapeake Bay, USA

2011 ◽  
Vol 35 (1) ◽  
pp. 237-261 ◽  
Author(s):  
Jiangtao Xu ◽  
Wen Long ◽  
Jerry D. Wiggert ◽  
Lyon W. J. Lanerolle ◽  
Christopher W. Brown ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
Climate Forcing ◽  
Salinity Variability

scholarly journals Adaptations by Zostera marina Dominated Seagrass Meadows in Response to Water Quality and Climate Forcing

Diversity ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 125 ◽  
Author(s):  
Erin Shields ◽  
Kenneth Moore ◽  
David Parrish
Keyword(s):  
Water Quality ◽  
Chesapeake Bay ◽  
Zostera Marina ◽  
Human Disturbance ◽  
Climatic Factors ◽  
Water Clarity ◽  
Growth Patterns ◽  
Climate Forcing ◽  
Seagrass Meadows ◽  
Response To Water

Global assessments of seagrass declines have documented accelerating rates of loss due to anthropogenic sediment and nutrient loadings, resulting in poor water quality. More recently, global temperature increases have emerged as additional major stressors. Seagrass changes in the Chesapeake Bay, USA provide important examples of not only the effects of human disturbance and climate forcing on seagrass loss, but also meadow recovery and resiliency. In the York River sub-tributary of the Chesapeake Bay, the meadows have been monitored intensively using annual aerial imagery, monthly transect surveys, and continuous water quality measurements. Here, Zostera marina has been demonstrating a shift in its historical growth patterns, with its biomass peaking earlier in the growing season and summer declines beginning earlier. We found an increasing trend in the length of the most stressful high temperature summer period, increasing by 22 days since 1950. Over the past 20 years, Z. marina’s abundance has exhibited periods of decline followed by recovery, with recovery years associated with greater spring water clarity and less time spent at water temperatures > 28 °C. Although human disturbance and climatic factors have been altering these seagrass meadows, resilience has been evident by an increase in reproductive output and regrowth from Z. marina seedlings following declines, as well as expansions of Ruppia maritima into areas previously dominated by Z. marina.

Sign in / Sign up

Export Citation Format

Share Document