scholarly journals Spatial and temporal trends in runoff at long-term streamgages within and near the Chesapeake Bay Watershed

2012 ◽  
Author(s):  
Karen C. Rice ◽  
Robert M. Hirsch
Keyword(s):  
Chesapeake Bay ◽  
Temporal Trends ◽  
Chesapeake Bay Watershed ◽  
Spatial And Temporal Trends

Long-term pCO2 dynamics in rivers in the Chesapeake Bay watershed

2013 ◽  
Vol 31 ◽  
pp. 209-215 ◽  
Author(s):  
M. Bala Krishna Prasad ◽  
Sujay S. Kaushal ◽  
Raghu Murtugudde
Keyword(s):  
Chesapeake Bay ◽  
Chesapeake Bay Watershed

scholarly journals Long-term spatial and temporal trends in frost indices in Kansas, USA

2013 ◽  
Vol 120 (1-2) ◽  
pp. 169-181 ◽  
Author(s):  
Aavudai Anandhi ◽  
Sriram Perumal ◽  
Prasanna H. Gowda ◽  
Mary Knapp ◽  
Stacy Hutchinson ◽  
...  
Keyword(s):  
Temporal Trends ◽  
Spatial And Temporal Trends

scholarly journals Worldwide atmospheric mercury measurements: a review and synthesis of spatial and temporal trends

2010 ◽  
Vol 10 (1) ◽  
pp. 1261-1307 ◽  
Author(s):  
F. Sprovieri ◽  
N. Pirrone ◽  
R. Ebinghaus ◽  
H. Kock ◽  
A. Dommergue
Keyword(s):  
Temporal Trends ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Water Soluble ◽  
Polar Regions ◽  
Mercury Emissions ◽  
Gaseous Mercury ◽  
National Programs ◽  
Spatial And Temporal Trends

Abstract. A large number of activities have been carried out during the last decade in different regions of the world, including polar regions, aiming to assess the level of mercury (Hg) species in ambient air and in precipitation observing their variation over time and with changing meteorological conditions. Following the discovery of atmospheric Hg depletion events (AMDEs) in Polar Regions several studies have indeed been conducted in order to assess the chemical-physical mechanisms related to AMDEs occurred in polar atmospheres with special attention to the consequences of these phenomena in terms of contamination of polar environment due to the rapid conversion of atmospheric gaseous Hg (Hg0) into reactive and water-soluble forms that may potentially become bioavailable. The understanding of the way in which mercury released to the atmosphere is eventually incorporated into biota is of crucial importance not only for the polar regions but also for the marine environment in general. The world's oceans and seas are in fact both sources and sinks of Hg and although it appears that the atmosphere is the major transport/distribution medium for Hg, because most Hg emissions are to the atmosphere, oceans and seas also play an important role. Currently, however, a coordinated observational network for Hg does not exist. There are a number of state and national programs that are collecting atmospheric Hg data but the parameters monitored, the locations of the monitoring sites and the methods employed may prohibit their utility in assessing Hg long-trend variations. The large increase in mercury emissions in fast developing countries (i.e., China, India) over the last decade due primarily to a sharp increase in energy production from the combustion of coal are not currently reflected in the long-term measurements of total gaseous mercury in ambient air and in precipitation data at several continuous monitoring sites in North Europe and North America. The discrepancy between observed gaseous mercury concentrations (steady or decreasing) and global mercury emission inventories (increasing) is not yet clear however, could be at least in part accounted by the increasing in the potential oxidation of the atmosphere recently documented. Therefore, measurements of other key atmospheric constituents at the global monitoring sites are necessary for us to develop a better understanding of the global redistribution of Hg and to further refine model parameterizations of the key processes. The sharing of data from this network, allowing, in fact, access to comparable and long-term data from a wide array of locations for understanding temporal and spatial patterns of Hg transport, deposition and re-emission process producing thus data that will support the validation of regional and global atmospheric Hg models. This paper presents a detailed overview of atmospheric mercury measurements conducted in the Northern and Southern Hemispheres at several terrestrial sites (industrial, rural and remote) during the last decade as well as measurements performed over the world's ocean and seas and in Polar Regions with reference to the monitoring techniques and location of monitoring sites in most of the continents.

scholarly journals Trends of some rare flora species populations in the Southern Urals foothills (Orenburg Region)

2019 ◽  
Vol 8 (1) ◽  
pp. 99-105
Author(s):  
Maksim Anatolievich Safonov
Keyword(s):  
Temporal Trends ◽  
Southern Urals ◽  
Meadow Steppe ◽  
The Southern Urals ◽  
Pasture Load ◽  
Steppe Ecosystems ◽  
Epipactis Helleborine ◽  
Spatial And Temporal Trends ◽  
A New Species

The results of long-term (1994-2018) studies of the distribution and abundance of rare plant species in the foothills of the Southern Urals in order to identify their spatial and temporal trends are discussed. Some species retains its low numbers; in some species the number of populations and their amount were reduced, and some, probably, entirely disappeared from the flora. It is a new species in the local flora - Bupleurum aureum , but its low number does not allow to assess objectively its status and the necessary measures of protection. Spreading of Epipactis helleborine is also sporadic. The population of Veratrum lobelianum is gradually spreading to the South due to mesophytization of the climate and changes in pasture load on meadow and meadow-steppe ecosystems. The populations of the Cicerbita uralensis and Lathyrus litvinovii are in the critical condition. Thus, the change in environmental conditions leads to the fact that simultaneously with the reduction of the rare fraction, some species that previously had a small number, begin resettlement, contributing to the change in the appearance of the vegetation cover of the southern Urals foothills.

scholarly journals Sediment dynamics and implications for management: State of the science from long‐term research in the Chesapeake Bay watershed, USA

2020 ◽  
Vol 7 (4) ◽  
Author(s):  
Gregory B. Noe ◽  
Matthew J. Cashman ◽  
Katie Skalak ◽  
Allen Gellis ◽  
Kristina G. Hopkins ◽  
...  
Keyword(s):  
Chesapeake Bay ◽  
Sediment Dynamics ◽  
Chesapeake Bay Watershed ◽  
State Of The Science
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