Projected precipitation changes within the Great Lakes and Western Lake Erie Basin: a multi‐model analysis of intensity and seasonality

The Great Lakes region encompasses the largest freshwater lake network in the world and supports a diverse network of agriculture, transportation, and tourism. Recently, Lake Erie has experienced increased hypoxia events, which have been attributed to agricultural practices and changes in run‐off. Here we examine the projected changes in extreme precipitation events to address concerns regarding regional agriculture, surface run‐off, and subsequent water quality. Precipitation projections within the overall Great Lakes Basin and the Western Lake Erie Basin subregion are examined using climate model simulations of varying spatial resolutions to understand historical precipitation and projected future precipitation. We develop three model ensembles for the historical period (1980–1999) and the mid‐century (2041–2060) that cover a range of spatial resolutions and future emissions scenarios, including: (1) 12 global model members from the fifth Climate Model Intercomparison Project (CMIP5) using Representative Concentration Pathway (RCP) 8.5, (2) ten regional climate model (RCM) members from the North American Regional Climate Change Assessment Program driven by CMIP3 global models using the A2 emissions scenario, and (3) two high resolution RCM simulations (RCM4) driven by CMIP5 global models using the RCP 8.5 scenario. For the historical period, all model ensembles overestimate winter and spring precipitation, and many of the models simulate a summer drying that is not observed. At mid‐century, most of the models predict a 10–20% increase in precipitation depending on the time of year. Daily probability distribution functions from three model ensembles reveal spring seasonal increases in high precipitation event probabilities when compared to the historical period, suggesting an increase in the frequency of high intensity precipitation at mid‐century. Overall, the presence of lakes or higher spatial resolution does not ensure improved representation of historical processes, and more complex interactions between large‐scale dynamics, local feedbacks, and physical parameterizations drive the model spread.We examine extreme precipitation events in the Great Lakes and the Western Lake Erie Basin using global and regional climate model simulations of to understand historical precipitation and projected future mid‐century precipitation. At mid‐century, most models predict a 10–20% precipitation increase and an increase in the frequency of high intensity precipitation at mid‐century. The presence of lakes or higher spatial resolution does not ensure improved representation of precipitation and large‐scale dynamics, local feedbacks, and physical parameterizations drive the model spread.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139100/1/joc5128.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139100/2/joc5128_am.pd

Biogenic 2‐methyl‐3‐buten‐2‐ol increases regional ozone and HO x sources

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95042/1/grl23505.pd

Simulação do Balanço de Energia com os Esquemas Bats e Clm sobre a América do Sul

In the present work two simulations with the land surfaceschemes BATS (RegBATS) and CLM (RegCLM) coupled in the RegCM3are evaluated. The larger differences between RegCLM and RegBATS arefound in the Amazon region, when the RegCLM reduces the excessiveevapotranspirantion simulated by the RegBATS during the wet season.In contrast, in the dry season RegCLM overestimates the sensible heatingtransfer, increasing the air temperature.No presente trabalho são comparados duas simulações contínuasde 2,5 anos com os esquemas de superfície BATS (RegBATS) eCLM (RegCLM) acoplados ao modelo RegCM3. As maiores diferençasentre o RegCLM e RegBATS são encontradas na região Amazônica, quandoo RegCLM reduz a excessiva evapotranspiração do RegBATS durantea estação chuvosa. Por outro lado, na estação seca o RegCLM superestimaa transferência de calor sensível, com conseqüente aumento da temperaturado ar

Costs of school transportation: quantifying the fiscal impacts of encouraging walking and bicycling for school travel

Abstract National governments have provided subsidies for investments in increasing the safety and attractiveness of walking and biking to school. Evaluations of Safe Routes to School initiatives have found that they have been effective at changing behavior and reducing injuries. However, there has been little attention to the impacts of these programs on pupil transportation costs. This analysis assesses the potential economic benefits of Safe Routes to School programs in the US context by estimating the annual costs of using motorized transport for short trips to schools, examining real-world examples of the costs savings of SRTS programs, and evaluating land use impacts on school transportation costs using a simulation analysis of school bus routes. We find that there is potential for school districts and families to reduce transport expenditures through public sector investments in walking and biking infrastructure near schools. We also find that land use context matters and the most cost-effective investments would benefit schools where large numbers of children live within walking distance

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided by phase 3 of the Coupled Model Intercomparison Project (CMIP3) were employed as boundary conditions. There is a broad consensus among the simulations, despite differences in the simulated climate trajectories across the ensemble, that about half of the needleleaf evergreen tree coverage (from 24% to 11%) will disappear, coincident with a 14% (from 11% to 25%) increase in shrubs and grasses by the end of the twenty-first century in western NA, with most of the change occurring over the latter half of the twenty-first century. The net impact is a ~6 GtC or about 50% decrease in projected ecosystem carbon storage in this region. The findings suggest a potential for a widespread shift from tree-dominated landscapes to shrub and grass-dominated landscapes in western NA because of future warming and consequent increases in water deficits. These results highlight the need for improved process-based understanding of vegetation dynamics, particularly including mortality and the subsequent incorporation of these mechanisms into earth system models to better quantify the vulnerability of western NA forests under climate change

Projected Future Changes in Vegetation in Western North America in the Twenty-First Century

Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided by phase 3 of the Coupled Model Intercomparison Project (CMIP3) were employed as boundary conditions. There is a broad consensus among the simulations, despite differences in the simulated climate trajectories across the ensemble, that about half of the needleleaf evergreen tree coverage (from 24% to 11%) will disappear, coincident with a 14% (from 11% to 25%) increase in shrubs and grasses by the end of the twenty-first century in western NA, with most of the change occurring over the latter half of the twenty-first century. The net impact is a ~6 GtC or about 50% decrease in projected ecosystem carbon storage in this region. The findings suggest a potential for a widespread shift from tree-dominated landscapes to shrub and grass-dominated landscapes in western NA because of future warming and consequent increases in water deficits. These results highlight the need for improved process-based understanding of vegetation dynamics, particularly including mortality and the subsequent incorporation of these mechanisms into earth system models to better quantify the vulnerability of western NA forests under climate change

Atmo-ecometabolomics : a novel atmospheric particle chemical characterization methodology for ecological research

Aerosol particles play important roles in processes controlling the composition of the atmosphere and function of ecosystems. A better understanding of the composition of aerosol particles is beginning to be recognized as critical for ecological research to further comprehend the link between aerosols and ecosystems. While chemical characterization of aerosols has been practiced in the atmospheric science community, detailed methodology tailored to the needs of ecological research does not exist yet. In this study, we describe an efficient methodology (atmo-ecometabolomics), in step-by-step details, from the sampling to the data analyses, to characterize the chemical composition of aerosol particles, namely atmo-metabolome. This method employs mass spectrometry platforms such as liquid and gas chromatography mass spectrometries (MS) and Fourier transform ion cyclotron resonance MS (FT-ICR-MS). For methodology evaluation, we analyzed aerosol particles collected during two different seasons (spring and summer) in a low-biological-activity ecosystem. Additionally, to further validate our methodology, we analyzed aerosol particles collected in a more biologically active ecosystem during the pollination peaks of three different representative tree species. Our statistical results showed that our sampling and extraction methods are suitable for characterizing the atmo-ecometabolomes in these two distinct ecosystems with any of the analytical platforms. Datasets obtained from each mass spectrometry instrument showed overall significant differences of the atmo-ecometabolomes between spring and summer as well as between the three pollination peak periods. Furthermore, we have identified several metabolites that can be attributed to pollen and other plant-related aerosol particles. We additionally provide a basic guide of the potential use ecometabolomic techniques on different mass spectrometry platforms to accurately analyze the atmo-ecometabolomes for ecological studies. Our method represents an advanced novel approach for future studies in the impact of aerosol particle chemical compositions on ecosystem structure and function and biogeochemistry

Cellular and Molecular Bases of the Initiation of Fever

All phases of lipopolysaccharide (LPS)-induced fever are mediated by prostaglandin (PG) E(2). It is known that the second febrile phase (which starts at ~1.5 h post-LPS) and subsequent phases are mediated by PGE(2) that originated in endotheliocytes and perivascular cells of the brain. However, the location and phenotypes of the cells that produce PGE(2) triggering the first febrile phase (which starts at ~0.5 h) remain unknown. By studying PGE(2) synthesis at the enzymatic level, we found that it was activated in the lung and liver, but not in the brain, at the onset of the first phase of LPS fever in rats. This activation involved phosphorylation of cytosolic phospholipase A(2) (cPLA(2)) and transcriptional up-regulation of cyclooxygenase (COX)-2. The number of cells displaying COX-2 immunoreactivity surged in the lung and liver (but not in the brain) at the onset of fever, and the majority of these cells were identified as macrophages. When PGE(2) synthesis in the periphery was activated, the concentration of PGE(2) increased both in the venous blood (which collects PGE(2) from tissues) and arterial blood (which delivers PGE(2) to the brain). Most importantly, neutralization of circulating PGE(2) with an anti-PGE(2) antibody both delayed and attenuated LPS fever. It is concluded that fever is initiated by circulating PGE(2) synthesized by macrophages of the LPS-processing organs (lung and liver) via phosphorylation of cPLA(2) and transcriptional up-regulation of COX-2. Whether PGE(2) produced at the level of the blood–brain barrier also contributes to the development of the first phase remains to be clarified

The role of soil ice in land‐atmosphere coupling over the United States: A soil moisture–precipitation winter feedback mechanism

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95620/1/jgrd16563.pd