Entire DC Network | Open Access Articles | Digital Commons Network™

Rising Minimum Daily Flows In Northern Eurasian Rivers: A Growing Influence Of Groundwater In The High‐Latitude Hydrologic Cycle, Laurence C. Smith, Tamlin M. Pavelsky, Glen M. Macdonald, Alexander I. Shiklomanov, Richard B. Lammers

Faculty Publications

A first analysis of new daily discharge data for 111 northern rivers from 1936–1999 and 1958–1989 finds an overall pattern of increasing minimum daily flows (or “low flows”) throughout Russia. These increases are generally more abundant than are increases in mean flow and appear to drive much of the overall rise in mean flow observed here and in previous studies. Minimum flow decreases have also occurred but are less abundant. The minimum flow increases are found in summer as well as winter and in nonpermafrost as well as permafrost terrain. No robust spatial contrasts are found between the European Russia, …

Go to article

Temporal And Spatial Variations In Maximum River Discharge From A New Russian Data Set, Alexander I. Shiklomanov, Richard B. Lammers, M. A. Rawlins, L. C. Smith, T. M. Pavelsky

Faculty Publications

Floods cause more damage in Russia than any other natural disaster, and future climate model projections suggest that the frequency and magnitude of extreme hydrological events will increase in Russia with climate change. Here we analyze daily discharge records from a new data set of 139 Russian gauges in the Eurasian Arctic drainage basin with watershed areas from 16.1 to 50,000 km2 for signs of change in maximum river discharge. Several hypotheses about changes in maximum daily discharge and their linking with trends in precipitation over the cold season were tested. For the magnitude of maximum daily discharge we found …

Go to article

Variability In River Temperature, Discharge, And Energy Flux From The Russian Pan‐Arctic Landmass, Richard B. Lammers, Jonathan W. Pundsack, Alexander I. Shiklomanov

Faculty Publications

We introduce a new Arctic river temperature data set covering 20 gauges in 17 unique Arctic Ocean drainage basins in the Russian pan‐Arctic (ART‐Russia). Warm season 10‐day time step data (decades) were collected from Russian archival sources covering a period from 1929 to 2003 with most data falling in the range from the mid‐1930s to the early 1990s. The water temperature data were combined with river discharge data to estimate energy flux for all basins and over the Russian pan‐Arctic as a whole. Tests for trend were carried out for water temperature, river discharge, and energy flux. Spatially coherent significant …

Go to article

A Large Terrestrial Source Of Methyl Iodide, Barkley C. Sive, Ruth K. Varner, Huiting Mao, Oliver W. Wingenter, Robert W. Talbot

Faculty Publications

We have identified terrestrial sources of methyl iodide (CH3I) and assessed their importance in its atmospheric budget using a synthesis of field observations. Measurements include those from NASA DC‐8 research flights over the United States and the North Atlantic, the AIRMAP long‐term ground‐observing network in New England, and a field campaign at Duke Forest, North Carolina. We found an average CH3I flux of ∼2,700 ng m−2 d−1 to the atmosphere from midlatitude vegetation and soils, a value similar in magnitude to previous estimates of the oceanic source strength. The large‐scale aircraft measurements of vertical profiles over the continental U.S. showed …

Go to article

Arctic, Chapter 5b In State Of The Climate In 2005, J. Richter-Menge, J. Overland, A. Proshutinsky, V. Romanovsky, J. C, Gascard, M. Karcher, J. Maslanik, D. Perovich, Alexander I. Shiklomanov, D. Walker

Faculty Publications

No abstract provided.

Go to article

Arctic, Chapter 5a In State Of The Climate In 2006, J. Richter-Menge, J. Overland, A. Proshutinsky, V. Romanovsky, R. Armstrong, J. Morison, S. Nghiem, N. Oberman, D. Perovich, I. Rigor, L. Bengtsson, R. Przybylak, Alexander I. Shiklomanov, D. Walker, J. Walsh

Faculty Publications

No abstract provided.

Go to article

Nanoparticle Growth Following Photochemical Α‐ And Β‐Pinene Oxidation At Appledore Island During International Consortium For Research On Transport And Transformation/Chemistry Of Halogens At The Isles Of Shoals 2004, L. M. Russell, A. A. Mensah, Emily V. Fischer, Barkley C. Sive, Ruth K. Varner, William C. Keene, Jochen Stutz, Alexander A. P. Pszenny

Faculty Publications

Nanoparticle events were observed 48 times in particle size distributions at Appledore Island during the International Consortium for Atmospheric Research on Transport and Transformation/Chemistry of Halogens on the Isles of Shoals (ICARTT/CHAiOS) field campaign from 2 July to 12 August of 2004. Eighteen of the nanoparticle events showed particle growth and occurred during mornings when peaks in mixing ratios of α‐ and β‐pinene and ozone made production of condensable products from photochemical oxidation probable. Many pollutants and other potential precursors for aerosol formation were also at elevated mixing ratios during these events, including NO, HNO3, NH3, HCl, propane, and several …

Go to article

Inorganic Chlorine And Bromine In Coastal New England Air During Summer, William C. Keene, Jochen Stutz, Alexander A. P. Pszenny, John R. Maben, Emily V. Fischer, Allen M. Smith, Roland Von Glasow, Susanne Pechtl, Barkley C. Sive, Ruth K. Varner

Faculty Publications

During summer 2004, a comprehensive suite of reactive trace gases (including halogen radicals and precursors, ozone, reactive N, soluble acids, and hydrocarbons), the chemical and physical characteristics of size‐resolved aerosols, actinic flux, and related physical conditions were measured at Appledore Island, Maine, as part of the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT). Sea‐salt mass averaged 4 to 8 times lower than that over the open North Atlantic Ocean. Production in association with sea salt was the primary source for inorganic Cl and Br. Acid displacement of sea‐salt Cl− primarily by HNO3 sustained high HCl mixing ratios …

Go to article

Estimates Of Cl Atom Concentrations And Hydrocarbon Kinetic Reactivity In Surface Air At Appledore Island, Maine (Usa), During International Consortium For Atmospheric Research On Transport And Transformation/Chemistry Of Halogens At The Isles Of Shoals, Alexander A. P. Pszenny, Emily V. Fischer, Rachel S. Russo, Barkley C. Sive, Ruth K. Varner

Faculty Publications

Average hydroxyl radical (OH) to chlorine atom (Cl·) ratios ranging from 45 to 119 were determined from variability‐lifetime relationships for selected nonmethane hydrocarbons (NMHC) in surface air from six different transport sectors arriving at Appledore Island, Maine, during July 2004. Multiplying these ratios by an assumed average OH concentration of 2.5 × 106 cm−3 yielded estimates of Cl· concentrations of 2.2 to 5.6 × 104 cm−3. Summed reaction rates of methane and more than 30 abundant NMHCs with OH and Cl· suggest that Cl· reactions increased the kinetic reactivity of hydrocarbons by 16% to 30% over that due to OH …

Go to article

Deviations From Ozone Photostationary State During The International Consortium For Atmospheric Research On Transport And Transformation 2004 Campaign: Use Of Measurements And Photochemical Modeling To Assess Potential Causes, Robert J. Griffin, Pieter J. Beckman, Robert W. Talbot, Barkley C. Sive, Ruth K. Varner

Faculty Publications

Nitric oxide (NO) and nitrogen dioxide (NO2) were monitored at the University of New Hampshire Atmospheric Observing Station at Thompson Farm (TF) during the ICARTT campaign of summer 2004. Simultaneous measurement of ozone (O3), temperature, and the photolysis rate of NO2 (jNO2) allow for assessment of the O3 photostationary state (Leighton ratio, Φ). Leighton ratios that are significantly greater than unity indicate that peroxy radicals (PO2), halogen monoxides, nitrate radicals, or some unidentified species convert NO to NO2 in excess of the reaction between NO and O3. Deviations from photostationary state occurred regularly at TF (1.0 ≤ Φ ≤ 5.9), …

Go to article

Timescale Dependence Of Environmental And Plant‐Mediated Controls On Ch4 Flux In A Temperate Fen, Claire C. Treat, Jill L. Bubier, Ruth K. Varner, Patrick M. Crill

Faculty Publications

This study examined daily, seasonal, and interannual variations in CH4 emissions at a temperate peatland over a 5‐year period. We measured net ecosystem CO2 exchange (NEE), CH4 flux, water table depth, peat temperature, and meteorological parameters weekly from the summers (1 May to 31 August) of 2000 through 2004 at Sallie's Fen in southeastern New Hampshire, United States. Significant interannual differences, driven by high variability of large individual CH4 fluxes (ranging from 8.7 to 3833.1 mg CH4 m−2 d−1) occurring in the late summer, corresponded with a decline in water table level and an increase in air and peat temperature. …

Go to article

Digital Commons Network^™

Full-Text Articles in Entire DC Network

Rising Minimum Daily Flows In Northern Eurasian Rivers: A Growing Influence Of Groundwater In The High‐Latitude Hydrologic Cycle, Laurence C. Smith, Tamlin M. Pavelsky, Glen M. Macdonald, Alexander I. Shiklomanov, Richard B. Lammers

Faculty Publications

Temporal And Spatial Variations In Maximum River Discharge From A New Russian Data Set, Alexander I. Shiklomanov, Richard B. Lammers, M. A. Rawlins, L. C. Smith, T. M. Pavelsky

Faculty Publications

Variability In River Temperature, Discharge, And Energy Flux From The Russian Pan‐Arctic Landmass, Richard B. Lammers, Jonathan W. Pundsack, Alexander I. Shiklomanov

Faculty Publications

A Large Terrestrial Source Of Methyl Iodide, Barkley C. Sive, Ruth K. Varner, Huiting Mao, Oliver W. Wingenter, Robert W. Talbot

Faculty Publications

Arctic, Chapter 5b In State Of The Climate In 2005, J. Richter-Menge, J. Overland, A. Proshutinsky, V. Romanovsky, J. C, Gascard, M. Karcher, J. Maslanik, D. Perovich, Alexander I. Shiklomanov, D. Walker

Faculty Publications

Arctic, Chapter 5a In State Of The Climate In 2006, J. Richter-Menge, J. Overland, A. Proshutinsky, V. Romanovsky, R. Armstrong, J. Morison, S. Nghiem, N. Oberman, D. Perovich, I. Rigor, L. Bengtsson, R. Przybylak, Alexander I. Shiklomanov, D. Walker, J. Walsh

Faculty Publications

Faculty Publications

Inorganic Chlorine And Bromine In Coastal New England Air During Summer, William C. Keene, Jochen Stutz, Alexander A. P. Pszenny, John R. Maben, Emily V. Fischer, Allen M. Smith, Roland Von Glasow, Susanne Pechtl, Barkley C. Sive, Ruth K. Varner

Faculty Publications

Faculty Publications

Faculty Publications

Timescale Dependence Of Environmental And Plant‐Mediated Controls On Ch4 Flux In A Temperate Fen, Claire C. Treat, Jill L. Bubier, Ruth K. Varner, Patrick M. Crill

Faculty Publications