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Full-Text Articles in Physical Sciences and Mathematics

Climate Changes In El Salvador: Impacts Of ‘La Canícula’ (Midsummer Drought) On Agricultural Practices And Decision-Making In Rural Communities, Paola M. Rivera González Jan 2023

Climate Changes In El Salvador: Impacts Of ‘La Canícula’ (Midsummer Drought) On Agricultural Practices And Decision-Making In Rural Communities, Paola M. Rivera González

Dissertations, Master's Theses and Master's Reports

The Central American Dry Corridor (CADC), a tropical, dry-forest region, is characterized by distinct rainy and dry seasons, which influence the local agricultural calendar and planting decisions in rural communities. La canícula is a period of decreased precipitation during the rainy season, which occurs during the corn-planting season in El Salvador. La canícula is expected to change in intensity and duration in the next decades, which would impact small-scale farmers and their livelihoods. Climate variability and uncertainty has led to crop loss, water scarcity, and food insecurity in rural communities dependent on subsistence farming. Farmers’ experiences with a changing climate …


The Changing Face Of Winter: Lessons And Questions From The Laurentian Great Lakes, Ted Ozersky, Andrew J. Bramburger, Ashley K. Elgin, Henry A. Vanderploeg, Jia Wang, Jay A. Austin, Guy Meadows, Et. Al. May 2021

The Changing Face Of Winter: Lessons And Questions From The Laurentian Great Lakes, Ted Ozersky, Andrew J. Bramburger, Ashley K. Elgin, Henry A. Vanderploeg, Jia Wang, Jay A. Austin, Guy Meadows, Et. Al.

Michigan Tech Publications

Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing winter precipitation patterns over the Laurentian Great Lakes and their watershed. Understanding and predicting the consequences of these changes is impeded by a shortage of winter-period studies on most aspects of Great Lake limnology. In this review, we summarize what is known about the Great Lakes during their 3–6 months of winter and identify key open questions about the physics, chemistry, and biology of the Laurentian Great Lakes and other large, seasonally frozen lakes. Existing studies show that winter conditions have …


Elucidating Peatland Disturbance Ecology And Carbon Dynamics Through The Lens Of Soil Using Infrared Spectrometry, Dominic Uhelski Jan 2021

Elucidating Peatland Disturbance Ecology And Carbon Dynamics Through The Lens Of Soil Using Infrared Spectrometry, Dominic Uhelski

Dissertations, Master's Theses and Master's Reports

We sought to quantify the fire regimes of peatlands in the hemi-boreal zone of North America, and to understand the qualities of their peat. We used infrared spectrometry to accomplish both goals by gathering spectral information about the organic matter in each sample. We used a series of mixtures of natural peat and natural peat charcoal to isolate the spectral components associated with charcoal concentration. We built a multiple linear regression model which predicts the charcoal concentration in peat samples. We validated our data using nuclear magnetic resonance spectrometry. As a result, we can accurately predict the charcoal concentration of …


Spatial And Temporal Variability Of Carbonaceous Aerosol Absorption In The Po Valley, Stefania Gilardoni, Paola Massoli, Angela Marinoni, Claudio Mazzoleni, Andrew Freedman, Giovanni Lonati, Silvana De Iuliis, Vorne Gianelle Dec 2020

Spatial And Temporal Variability Of Carbonaceous Aerosol Absorption In The Po Valley, Stefania Gilardoni, Paola Massoli, Angela Marinoni, Claudio Mazzoleni, Andrew Freedman, Giovanni Lonati, Silvana De Iuliis, Vorne Gianelle

Michigan Tech Publications

Knowledge gaps in the optical properties of carbonaceous aerosols account for a significant fraction of the uncertainty of aerosol-light interactions in climate models. Both black carbon (BC) and brown carbon (BrC) can display a range of optical properties in ambient aerosol due to different sources and chemical transformation pathways. This study investigates the optical absorption properties of BC and BrC at an urban and a rural site in the Po Valley (Italy), a known European pollution hot spot. We observed spatial and seasonal variability of aerosol absorption coefficients, with the highest values measured in winter at the urban site of …


Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp Jan 2019

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …


Long-Term Changes In Extreme Air Pollution Meteorology And Implications For Air Quality, Pei Hou Jan 2018

Long-Term Changes In Extreme Air Pollution Meteorology And Implications For Air Quality, Pei Hou

Dissertations, Master's Theses and Master's Reports

Extreme air pollution meteorology, such as heat waves, temperature inversions, and atmospheric stagnation episodes, can significantly affect air quality. In this study, we analyze their long-term trends and the potential impacts on air quality. The significant increasing trends for the occurrences of extreme meteorological events in 1951-2010 are identified with the reanalysis data, especially over the continental regions. A statistical analysis combining air quality data and meteorological data indicates strong sensitivities of air quality, including both average air pollutant concentrations and high pollution episodes, to extreme meteorological events. Results also show significant seasonal and spatial variations in the sensitivity of …


Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl Jan 2016

Assessing The Impacts Of Climate Change On The Surface Temperature Of Inland Lakes In Michigan, Kaitlin Reinl

Dissertations, Master's Theses and Master's Reports

The aim of this study was to validate and apply a lake model for predicting the susceptibility of small inland lakes in Michigan to changes in thermal regime and increased cyanobacteria growth as a result of future climate conditions. The Freshwater Lake Model was selected, tested for sensitivity to various inputs, and validated through comparison to observed conditions. The sensitivity analysis showed that the lake model was most sensitive to solar radiation, air temperature, and air humidity. Comparison of predicted climate data with observed conditions revealed highly variable climate model error. The lake model validation was conducted using 10 lakes …


Observational Bounds On Atmospheric Heating By Aerosol Absorption: Radiative Signature Of Transatlantic Dust, Amit Davidi, Alexander Kostinski, Ilan Koren, Yoav Lehahn Feb 2012

Observational Bounds On Atmospheric Heating By Aerosol Absorption: Radiative Signature Of Transatlantic Dust, Amit Davidi, Alexander Kostinski, Ilan Koren, Yoav Lehahn

Department of Physics Publications

[1] Aerosols absorb solar radiation thus changing the atmospheric temperature profile but the overall magnitude of this effect is not known. To that end, Saharan dust emissions over the Atlantic Ocean provide an opportunity to examine aerosol‐related heating via satellite imaging. A major difficulty, however, is disentangling a straightforward heating signal caused by the absorbing dust from a meteorological signal, which originates from correlation between dust concentration and air temperature. To tackle the problem, we combine temperature (T) soundings, from the atmospheric infrared sounder (AIRS), with aerosol optical depth (τ) measurements, from the moderate resolution imaging …