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Full-Text Articles in Physical Sciences and Mathematics

Attribution Of Spatial And Temporal Variations In Terrestrial Methane Flux Over North America, X. F. Xu, Hanqin Tian, C. Zhang, M. L. Liu, Wei Ren, G. S. Chen, Chaoqun (Crystal) Lu, L. Bruhwiler Nov 2010

Attribution Of Spatial And Temporal Variations In Terrestrial Methane Flux Over North America, X. F. Xu, Hanqin Tian, C. Zhang, M. L. Liu, Wei Ren, G. S. Chen, Chaoqun (Crystal) Lu, L. Bruhwiler

Chaoqun (Crystal) Lu

The attribution of spatial and temporal variations in terrestrial methane (CH4) flux is essential for assessing and mitigating CH4 emission from terrestrial ecosystems. In this study, we used a process-based model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with spatial data of six major environmental factors to attribute the spatial and temporal variations in the terrestrial methane (CH4) flux over North America from 1979 to 2008 to six individual driving factors and their interaction. Over the past three decades, our simulations indicate that global change factors accumulatively contributed 23.51 ± 9.61 T g CH4-C (1 Tg = 1012 g) …


Characterization Of Pollen Particles Using Lidar, Leda Sox Oct 2010

Characterization Of Pollen Particles Using Lidar, Leda Sox

Leda Sox

We have observed pollen in the local troposphere using the depolarization capabilities of a LIDAR (Light Detection and Ranging) system. The polarization characteristics of the received LIDAR signal, along with supplemental pollen forecast data, allowed me to characterize the shape of the pollen particles.


Wave-Induced Transport Of Atmospheric Constituents And Its Effect On The Mesospheric Na Layer, Chester S. Gardner, Alan Z. Liu Oct 2010

Wave-Induced Transport Of Atmospheric Constituents And Its Effect On The Mesospheric Na Layer, Chester S. Gardner, Alan Z. Liu

Alan Z Liu

No abstract provided.


Hf Radar Performance In A Low-Energy Environment: Codar Seasonde Experience On The West Florida Shelf, Yonggang Liu, Robert H. Weisberg, Clifford R. Merz, Sage Litchtenwalner, Gary J. Kirkpatrick Oct 2010

Hf Radar Performance In A Low-Energy Environment: Codar Seasonde Experience On The West Florida Shelf, Yonggang Liu, Robert H. Weisberg, Clifford R. Merz, Sage Litchtenwalner, Gary J. Kirkpatrick

Yonggang Liu

Three long-range (5 MHz) Coastal Ocean Dynamics Application Radar (CODAR) SeaSonde HF radars overlooking an array of as many as eight moored acoustic Doppler current profilers (ADCPs) have operated on the West Florida Shelf since September 2003 for the purpose of observing the coastal ocean currents. HF radar performance on this low-energy (currents and waves) continental shelf is evaluated with respect to data returns, the rms differences between the HF radar and the ADCP radial currents, bearing offsets, and radial velocity uncertainties. Possible environmental factors affecting the HF radar performance are discussed, with the findings that both the low-energy sea …


Chemistry–Climate Model Simulations Of Twenty-First Century Stratospheric Climate And Circulation Changes, Neal Butchart, I. Cionni, V. Eyring, T. G. Shepherd, D. W. Waugh, H. Akiyoshi, J. Austin, C. Brühl, M. P. Chipperfield, Eugene C. Cordero, M. Dameris, R. Deckert, S. Dhomse, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, D. E. Kinnison, F. Li, E. Mancini, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, F. Sassi, J. F. Scinocca, K. Shibata, B. Steil, W. Tian Oct 2010

Chemistry–Climate Model Simulations Of Twenty-First Century Stratospheric Climate And Circulation Changes, Neal Butchart, I. Cionni, V. Eyring, T. G. Shepherd, D. W. Waugh, H. Akiyoshi, J. Austin, C. Brühl, M. P. Chipperfield, Eugene C. Cordero, M. Dameris, R. Deckert, S. Dhomse, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, D. E. Kinnison, F. Li, E. Mancini, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, F. Sassi, J. F. Scinocca, K. Shibata, B. Steil, W. Tian

Eugene C. Cordero

The response of stratospheric climate and circulation to increasing amounts of greenhouse gases (GHGs) and ozone recovery in the twenty-first century is analyzed in simulations of 11 chemistry–climate models using near-identical forcings and experimental setup. In addition to an overall global cooling of the stratosphere in the simulations (0.59 ± 0.07 K decade−1 at 10 hPa), ozone recovery causes a warming of the Southern Hemisphere polar lower stratosphere in summer with enhanced cooling above. The rate of warming correlates with the rate of ozone recovery projected by the models and, on average, changes from 0.8 to 0.48 K decade …


Spatial And Temporal Patterns Of Ch4 And N2o Fluxes In Terrestrial Ecosystems Of North America During 1979–2008: Application Of A Global Biogeochemistry Model, Hanqin Tian, X. Xu, M. Liu, Wei Ren, C. Zhang, G. Chen, Chaoqun (Crystal) Lu Sep 2010

Spatial And Temporal Patterns Of Ch4 And N2o Fluxes In Terrestrial Ecosystems Of North America During 1979–2008: Application Of A Global Biogeochemistry Model, Hanqin Tian, X. Xu, M. Liu, Wei Ren, C. Zhang, G. Chen, Chaoqun (Crystal) Lu

Chaoqun (Crystal) Lu

Continental-scale estimations of terrestrial methane (CH4) and nitrous oxide (N2O) fluxes over a long time period are crucial to accurately assess the global balance of greenhouse gases and enhance our understanding and prediction of global climate change and terrestrial ecosystem feedbacks. Using a process-based global biogeochemical model, the Dynamic Land Ecosystem Model (DLEM), we quantified simultaneously CH4 and N2O fluxes in North America's terrestrial ecosystems from 1979 to 2008. During the past 30 years, approximately 14.69 ± 1.64 T g C a−1 (1 T g = 1012 g) of CH4, and 1.94 ± 0.1 T g N a−1 of N2O …


Recent Advances In The Climate Change Biology Literature: Describing The Whole Elephant, A. Townsend Peterson, Shaily Menon, Xingong Li Aug 2010

Recent Advances In The Climate Change Biology Literature: Describing The Whole Elephant, A. Townsend Peterson, Shaily Menon, Xingong Li

Shaily Menon

Climate change biology is seeing a wave of new contributions, which are reviewed herein. Contributions treat shifts in phenology and distribution, and both document past and forecast future effects. However, many of the current wave of contributions are observational and correlational, and few are experimental in nature, and too often a conceptual framework in which to contextualize the results is lacking. An additional gap is the lack of effective cross-linking among areas of research, for example, connection of sea-level rise and climate change implications for distributions of species, or evolutionary adaptation studies with distributional shift studies. Although numerous important contributions …


全球变化与陆地系统综合集成模拟 ——新一代陆地生态系统动态模型 (Dlem), 汉勤 田, 明亮 刘, 弛 张, 巍 任, 小锋 徐, 广生 陈, 超群 吕, 波 陶 Aug 2010

全球变化与陆地系统综合集成模拟 ——新一代陆地生态系统动态模型 (Dlem), 汉勤 田, 明亮 刘, 弛 张, 巍 任, 小锋 徐, 广生 陈, 超群 吕, 波 陶

Chaoqun (Crystal) Lu

人类社会从陆地生态系统获取生产和生活资料的同时也作为一种干扰形式改变着地气之间的动态平衡。这三个既独立又相互耦合的子系统共同组成了一个复杂的陆地系统。如何深入理解这一系统的过程和机制是人类应对气候变化挑战的前提条件。陆地生态系统模型作为一种集成工具,已广泛应用于全球变化研究的各个领域,但从输入数据到模型结构和过程等诸多方面仍存在很大的不确定性。近年来,随着大气和地面生态观测网络的不断完善以及遥感等空间技术的不断强大,使陆地生态系统模型进一步发展和突破成为可能。新一代多因子驱动的陆地生态系统动态模型(Dynamic Land Ecosystem Model, DLEM) 正是在这一背景下 应运而生的。本文旨在介绍DLEM的主体框架、输入输出变量、关键过程、主要功能和特点。


Cap-And-Trade Legislation, John C. Dernbach Mar 2010

Cap-And-Trade Legislation, John C. Dernbach

John C. Dernbach

No abstract provided.


Model Estimates Of Net Primary Productivity, Evapotranspiration, And Water Use Efficiency In The Terrestrial Ecosystems Of The Southern United States During 1895–2007, Hanqin Tian, Guangsheng Chen, Mingliang Liu, Chi Zhang, Ge Sun, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Shufen Pan, Arthur Chappelka Mar 2010

Model Estimates Of Net Primary Productivity, Evapotranspiration, And Water Use Efficiency In The Terrestrial Ecosystems Of The Southern United States During 1895–2007, Hanqin Tian, Guangsheng Chen, Mingliang Liu, Chi Zhang, Ge Sun, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Shufen Pan, Arthur Chappelka

Chaoqun (Crystal) Lu

The effects of global change on ecosystem productivity and water resources in the southern United States (SUS), a traditionally ‘water-rich’ region and the ‘timber basket’ of the country, are not well quantified. We carried out several simulation experiments to quantify ecosystem net primary productivity (NPP), evapotranspiration (ET) and water use efficiency (WUE) (i.e., NPP/ET) in the SUS by employing an integrated process-based ecosystem model (Dynamic Land Ecosystem Model, DLEM). The results indicated that the average ET in the SUS was 710 mm during 1895–2007. As a whole, the annual ET increased and decreased slightly during the first and second half …


Changes In Extreme Climate Indices For The Northeastern United States, 1870-2006, Paula J. Brown, Raymond S. Bradley, Frank T. Keimig Jan 2010

Changes In Extreme Climate Indices For The Northeastern United States, 1870-2006, Paula J. Brown, Raymond S. Bradley, Frank T. Keimig

Raymond S Bradley

The northeastern United States is one of the most variable climates in the world, and how climate extremes are changing is critical to populations, industries, and the environment in this region.Along-term (1870–2005) temperature and precipitation dataset was compiled for the northeastern United States to assess how the climate has changed. Adjustments were made to daily temperatures to account for changes in mean, variance, and skewness resulting from inhomogeneities, but precipitation data were not adjusted. Trends in 17 temperature and 10 precipitation indices at 40 stations were evaluated over three time periods—1893–2005, 1893– 1950, and 1951–2005—and over 1870–2005 for a subset …


Determining Rates Of Virus Production In Aquatic Systems By The Virus Reduction Approach,, M.G. Weinbauer, J.M. Rowe, Steven Wilhelm Jan 2010

Determining Rates Of Virus Production In Aquatic Systems By The Virus Reduction Approach,, M.G. Weinbauer, J.M. Rowe, Steven Wilhelm

Steven Wilhelm

The reduction approach to assess virus production and the prokaryotic mortality by viral lysis stops new infection by reducing total virus abundance (and thus virus–host contacts). This allows for easy enumeration of viruses that originate from lysis of already infected cells due to the decreased abundance of free virus particles. This reoccurrence can be quantified and used to assess production and cell lysis rates. Several modifications of the method are presented and compared. The approaches have great potential for elucidating trends in virus production rates as well as for making generalized estimates of the quantitative effects of viruses on marine …


The Construction And Analysis Of Marker Gene Libraries, S.M. Short, F. Chen, Steven Wilhelm Jan 2010

The Construction And Analysis Of Marker Gene Libraries, S.M. Short, F. Chen, Steven Wilhelm

Steven Wilhelm

Marker genes for viruses are typically amplified from aquatic samples to determine whether specific viruses are present in the sample, or to examine the diversity of a group of related viruses. In this chapter, we will provide an overview of common methods used to amplify, clone, sequence, and analyze virus marker genes, and will focus our discussion on viruses infecting algae, bacteria, and heterotrophic flagellates. Within this chapter, we endeavor to highlight critical aspects and components of these methods. To this end, instead of providing a detailed experimental protocol for each of the steps involved in examining virus marker gene …


Inexpensive Time-Lapse Digital Cameras For Studying Transient Meteorological Phenomena: Dust Devils And Playa Flooding, Ralph D. Lorenz, Brian Jackson, Jason W. Barnes Jan 2010

Inexpensive Time-Lapse Digital Cameras For Studying Transient Meteorological Phenomena: Dust Devils And Playa Flooding, Ralph D. Lorenz, Brian Jackson, Jason W. Barnes

Brian Jackson

The authors describe the design and performance of inexpensive and compact time-lapse cameras suitable for field deployment in remote locations for long periods and their application to studying two time-variable meteorological phenomena in arid regions: desert dust devils and transient flooding of playa lakes. The camera units (with a total parts cost of ∼$80) are based around commercial “point and shoot” digital cameras, storing ∼1500 images on a solid-state memory card over a period between an hour to several months powered by alkaline batteries. A microcontroller can trigger image acquisition based on sensor inputs or at regular intervals. Some example …


Sonic Anemometer Calibrations, Michael Negale, David Cook Dec 2009

Sonic Anemometer Calibrations, Michael Negale, David Cook

Michael Negale

Initial conditions and boundary conditions are important for climate and atmospheric modeling. In order to get correct initial and boundary conditions, correct measurements need to be made. The eddy correlation flux measurement system (ECOR) is one such system that measures fluxes in momentum, sensible heat, latent heat, and carbon dioxide (CO2). These fluxes are calculated using the eddy covariance technique, which involves wind components, air temperature, water vapor, and CO2 concentration. The ECOR uses a fast response three-dimensional wind sensor, sonic anemometer (SA), to measure wind components and speed of sound, which is used to derive the air temperature. The …