J. D. Lenters

LimnoTech

Climate-driven disturbances threaten the sustainability of coastal communities in the Great Lakes Basin. Because such disturbances are unpredictable, their magnitude, number and intensity are changing, and they occur at varying temporal and spatial scales. Consequently, communities struggle to respond in effective ways. The expected intensification...

A multisensor snowfall observational suite has been deployed at the Marquette, Michigan, National Weather Service Weather Forecast Office (KMQT) since 2014. Micro Rain Radar (MRR; profiling radar), Precipitation Imaging Package (PIP; snow particle imager), and ancillary ground-based meteorological observations illustrate the unique capabilities of...

Climate change is one of the most severe threats to global lake ecosystems. Lake surface conditions, such as ice cover, surface temperature, evaporation and water level, respond dramatically to this threat, as observed in recent decades. In this Review, we discuss physical lake variables and their responses to climate change. Decreases in winter ic...

Large lakes of the world are habitats for diverse species, including endemic taxa, and are valuable resources that provide humanity with many ecosystem services. They are also sentinels of global and local change, and recent studies in limnology and paleolimnology have demonstrated disturbing evidence of their collective degradation in terms of dep...

Lake-effect snow (LeS) storms are driven by strong turbulent surface layer (SL) and planetary boundary layer (PBL) fluxes of heat and moisture caused by the flow of cold air over relatively warm water. To investigate the sensitivity of simulated LeS to the parameterization of SL and PBL turbulence, high-resolution simulations of two major storms, d...

Variations in climate have important influences on the hydrologic cycle. Observations over the continental U.S. in recent decades show substantial changes in hydrologically significant variables, such as decreases in cloud cover and increases in solar radiation (i.e., “solar brightening”), as well as increases in air temperature, changes in wind sp...

Turbulent fluxes of latent and sensible heat are important physical processes that influence the energy and water budgets of the North American Great Lakes. These fluxes can be measured in situ using eddy covariance techniques and are regularly included as a component of lake–atmosphere models. To help ensure accurate projections of lake temperatur...

Heat fluxes at the lake surface play an integral part in determining the energy budget and thermal structure in lakes, including regulating how lakes respond to climate change. We explore patterns in turbulent heat fluxes, which vary across temporal and spatial scales, using in situ high‐frequency monitoring data from 45 globally distributed lakes....

Study Region: The Nebraska Sand Hills consisting of four major land cover types: (1) lakes and wetlands (∼5% for both), (2) subirrigated meadows (∼10%), (3) dry valleys (∼20%), and (4) upland dunes (∼65%). Study Focus: Examination of surface energy and water balances on multiple temporal scales with primary focus on latent heat flux (λE), and evapo...

The modelling community has identified challenges for the integration and assessment of lake models due to the diversity of modelling approaches and lakes. In this study, we develop and assess a one-dimensional lake model and apply it to 32 lakes from a global observatory network. The data set included lakes over broad ranges in latitude, climatic...

Turbulent fluxes of latent and sensible heat are important physical processes that influence the energy and water budgets of the North American Great Lakes. Validation and improvement of bulk flux algorithms to simulate these turbulent heat fluxes are critical for accurate prediction of lake hydrodynamics, water levels, weather, and climate over th...

Despite potential evaporation rates in excess of the local precipitation, dry climates often support saline lakes through groundwater inputs of water and associated solutes. These groundwater-fed lakes are important indicators of environmental change, in part because their shallow water levels and salinity are very sensitive to weather and climatic...

Turbulent fluxes across the air-water interface are integral to determining lake heat budgets, evaporation, and carbon emissions from lakes. The stability of the atmospheric boundary layer (ABL) influences the exchange of turbulent energy. We explore the differences in over-lake ABL stability using data from 39 globally distributed lakes. The frequ...

The energy and water balance of a Phragmites australis dominated wetland in south central Nebraska was analyzed to assess consumptive water use and the potential for “water savings” as a result of vegetation eradication via herbicide treatment. Energy balance measurements were made at the field site for two growing seasons (treated and untreated),...

Pulling together long-term data is increasingly important in assessing environmental changes, whether regionally or globally.

In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, l...

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...

Significant trends in Lake Superior water temperature and ice cover have been observed in recent decades, and these trends have typically been analyzed using standard linear regression techniques. Although the linear trends are statistically significant and contribute to an understanding of environmental change, a careful examination of the trends...

Regional- to global-scale lake maps can now be produced using existing technology and freely available data and serve as powerful tools for a variety of lake- and water-related studies. The accuracy of these studies depends in part on the accuracy of the lake map that they use. Mapping lakes using remote sensing requires a careful study of error an...

Feedbacks between ice extent and evaporation have long been suspected to be important for Lake Superior evaporation because it is during autumn and winter when latent heat fluxes are highest. Recent direct measurements of evaporation made at the Stannard Rock Lighthouse have provided new information on the physical controls on Lake Superior evapora...

Miscanthus is an intriguing cellulosic bioenergy feedstock because its aboveground productivity is high for low amounts of agrochemical inputs, but soil temperatures below -3.5°C could threaten successful cultivation in temperate regions. We used a combination of observed soil temperatures and the Agro-IBIS model to investigate how strategic residu...

Soil temperature observation sites used in model validation and minimum soil temperature assessment. List of observation sites that were used to validate Agro-IBIS and for further assessment of annual minimum extreme 10 cm soil temperatures across the Midwest US. Soil surface refers to ground cover present; initial year is the beginning of the obse...

Several recent studies have reported that global and regional climate change has significant impacts on lake temperatures worldwide. However, the underlying mechanisms of the observed lake warming and the spatial patterns in trends at the global scale are currently not well understood. The Global Lake Temperature Collaboration (GLTC) was recently e...

First Global Lake Temperature Collaboration (GLTC) Workshop; Lincoln, Nebraska, 1-5 June 2012 It is widely recognized that climate change is affecting terrestrial and aquatic ecosystems. Recent studies have revealed significant warming of lakes throughout the world, and this rate of warming is often larger than that of the ambient air temperature (...

Mechanisms to remove Common reed (Phragmites australis) typically include a combination of herbicide applications and mechanical cutting or plowing of the soil. The objective of this study was to remove P. australis by various mechanisms and measure the subsequent short-term release of nutrients via simulated rain events. Three rain events of simil...

Detailed bathymetric data were collected for 28 thermokarst lakes across the Arctic Coastal Plain (ACP) of northern Alaska from areas with distinctly different surficial sediments and topography. Lakes found in the low-relief coastal area have developed in marine silts that are ice-rich in the upper 6–10 m. The lakes tend to be shallow (~ 2 m), of...

In summer 2010, water temperature profile measurements were made in 12 thermokarst lakes along a 150-km long north–south transect across the Arctic Coastal Plain of northern Alaska. In shallow lakes, gradual warming of the water column to 1–4°C begins at the lake bed during decay of the ice cover in spring. Rapid warming follows ice-off, with water...

Evapotranspiration (ET) is a significant component of the water and energy balance in wetlands and riparian zones, yet it is also one of the most challenging components to estimate. Diurnal water table fluctuations can be used to directly measure groundwater consumption by phreatophytes, which are often important contributors to the total ET in rip...

Emissions of salt dust from the shores of saline lakes significantly impact lake chemistry, air quality, transportation, human health, and climate. Quantitative methods for assessing these emissions, however, are still in the developmental stage. We investigate salt pathways from groundwater to dust using an approach that takes advantage of opportu...

1] High-frequency physical observations from 40 temperate lakes were used to examine the relative contributions of wind shear (u *) and convection (w *) to turbulence in the surface mixed layer. Seasonal patterns of u * and w * were dissimilar; u * was often highest in the spring, while w * increased throughout the summer to a maximum in early fall...

We investigate the observed positive trends in annual runoff in several basins in central Nebraska using the Budyko hypothesis as a diagnostic tool. In basins where runoff is dominated by base flow we found that the estimated annual evapotranspiration (ETa) to precipitation (P) ratio (ETa/P) from data is negatively related to the aridity index (ETp...

The surface energy balance of Lake Superior was measured using the eddy covariance method at a remote, offshore site at 0.5-h intervals from June 2008 through November 2010. Pronounced seasonal patterns in the surface energy balance were observed, with a five-month delay between maximum summer net radiation and maximum winter latent and sensible he...

Shallow, thermokarst lakes - which develop atop permafrost - are a prominent landscape feature on the Arctic Coastal Plain (ACP) of northern Alaska. The ACP is vulnerable to ongoing climate change and landscape modification, as thousands of thaw lakes and ponds are impacted by changes in temperature, precipitation, thawing permafrost, and human act...

About half of the Arctic Coastal Plain (ACP) of northern Alaska is covered with thermokarst lakes and drained lake basins, making lakes a dominant landscape element and a crucial component of the Arctic permafrost system. However, to date there has been no systematic collection of key lake parameters or baseline data with which to make spatial and...

Evapotranspiration (ET) impacts local and regional hydrologic organization on various spatial and temporal scales. Due to the importance of the Ogallala (High Plains) Aquifer, accurate estimation of ET in the Great Plains is vital for efficient water resource management. One of the areas with the largest saturated thickness in this region (the Sand...

Vegetation plays an important role in the surface energy and water balance of wetlands. Transpiration from phreatophytes, in particular, withdraws water directly from groundwater, often impacting streamflow rates in adjacent tributaries. In the Republican River basin of the Central Plains (USA), streamflow has declined significantly in the past 30-...

A number of recent numerical modeling studies have demonstrated a strong control of shallow groundwater table on evapotranspiration and land surface-atmosphere interactions. It has been previously shown that neglecting the role of groundwater in land surface models may result in significant errors in the surface energy and water balance, especially...

Recent studies have revealed significant warming of lakes throughout the world, and the observed rate of lake warming is - in many cases - more rapid than that of the ambient air temperature. These large changes in lake temperature have profound implications for lake hydrodynamics, productivity, and biotic communities. The scientific community is j...

Strong trends in surface water temperature and ice cover over Lake Superior have been observed in recent decades, and these trends have typically been analyzed using simple linear regression techniques. Although the linear trends are statistically significant and contribute to an understanding of lake change, a careful examination of the trends sho...

Evapotranspiration (ET) is a significant component of the water and energy balance in wetlands and riparian zones, yet it is also one of the most challenging components to estimate. Diurnal water table fluctuations can be used to directly measure groundwater consumption by phreatophytes, which are often important contributors to the total ET in rip...

Climate and vegetation strongly influence the water cycle on local to regional scales. A change in the surface energy and water balance, especially in dry climatic regions, can have a significant impact on local water availability and, therefore, water resource management. The purpose of this study is to quantify the energy and water balance of a r...

Water consumed through evapotranspiration (ET) impacts local and regional hydrologic regimes on various spatial and temporal scales. Estimating ET in the Great Plains is a prerequisite for effective regional water resource management of the Ogallala (High Plains) Aquifer, which supplies vital water resources in the form of irrigation for extensive...

Ethanol production from corn (Zea mays L.) has become a new avenue for economic vitality in the state of Nebraska. Although economic, technological and political analyses have previously been performed, this study aims to analyze a suite of environmental variables specific to corn production in Nebraska. The overall objective of this research is to...

Shallow endorheic saline lakes are common in semi-arid environments in North America, Africa, Asia, and Australia. These lakes receive minimal surface runoff and are supported by groundwater seepage. A combination of hydrologic and geologic factors (regional groundwater flow, evaporation, precipitation, lake size, groundwater recharge, and geologic...

Water temperature profile measurements were collected from 12 arctic lakes on the Arctic Coastal Plain of northern Alaska in summer 2010 as part of a network of lakes being studied. The lakes (> 1 km2) are underlain by permafrost and extend inland across some 150 km - from the Arctic coast near Barrow southward to the foothills of the Brooks Range....

The interactions between shallow groundwater and land surface processes, mediated by capillary rise processes from groundwater, may play an important role in the ecohydrology of riparian zones in both humid and semi-arid ecosystems. Some recent land surface models (LSM) incorporate the contribution of groundwater to land surface processes with vary...

The interactions between shallow groundwater and land surface processes, mediated by capillary rise processes from groundwater, may play an important role in the ecohydrology of riparian zones in both humid and semi-arid ecosystems. Some recent land surface models (LSM) incorporate the contribution of groundwater to land surface processes with vary...

The relationship between the El Niño-Southern Oscillation (ENSO) and hydrologic variability in the United States is investigated using Empirical Orthogonal Function (EOF)/Principal Component Analysis (PCA). The multivariate ENSO index (MEI) is utilized to identify strong coherences associated with multiple months (1-, 2-, 4-, 6-, 12-, 24-, 48-month...

The Sandhills region of western Nebraska comprises the largest stabilized dune field in the western hemisphere. Although situated in a semi-arid climate, the sandy soils allow a significant fraction of the ambient precipitation to drain through and recharge the underlying Ogallala aquifer. As part of the larger High Plains aquifer that extends from...

Thermokarst lakes are a prominent feature of the landscape on the Arctic Coastal Plain of northern Alaska. Otherwise known as ``thaw lakes,'' these shallow, water-filled depressions form in subsiding tundra in response to thawing permafrost. Occasionally, these lakes will drain and refill, sometimes undergoing numerous life cycles, and eventually l...

Variations in climate have a significant impact on the energy and water balance of lakes. Increases in water temperature, reductions in ice cover, and increases in evaporation are just a few examples of how some lakes are responding to global and regional warming. Interestingly, some lakes appear to be warming faster than the regional air temperatu...

Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere-land surface-lake climate models that could be used for both of these types of study simultaneously do not presently exist, though there ar...

Partitioning of precipitation between evapotranspiration and runoff at the basin scale is primarily controlled by climate and basin characteristics. Here we use the Budyko hypothesis to investigate the impacts of soil texture and groundwater (e.g., baseflow) on annual and long-term mean annual water balances of basins in a semiarid region located i...

Simple models of annual and mean annual basin runoff and evapotranspiration, such as the one proposed by Budyko (1963), are useful for investigating the relationship between the components of water balance and climate. Those models are often based on the assumption that annual precipitation is in balance with annual runoff and evapotranspiration, a...

Lakes on the coastal plain of arctic Alaska have developed atop continuous permafrost. Recent research suggests that lake levels, rates of bank erosion and drainage, and depth of the thaw bulb in sediments beneath the lake may increase in response to a warmer and wetter climate. Assessment of lake dynamics entails separating seasonal and interannua...

Variations in lake evaporation have a significant impact on the energy and water budgets of lakes. Understanding these variations and the role of climate is important for water resource management as well as predicting future changes in lake hydrology as a result of climate change. However, accurate monitoring of evaporation from water bodies requi...

Variations in lake evaporation have a significant impact on the energy and water budgets of lakes. Understanding these variations and the role of climate is important for water resource management as well as predicting future changes in lake hydrology as a result of climate change. This study presents a comprehensive, 10-year analysis of seasonal,...

An analysis of Lake Superior water levels from 1948–1999 reveals that the seasonal cycle has decreased in amplitude by 20% (from 40 cm to 32 cm). This change is manifested as a downward trend in summer and autumn lake levels (when levels are typically highest) accompanied by roughly no change in winter and spring lake levels (and an overall 4-cm dr...

Water levels in the Laurentian Great Lakes experience a fairly pronounced seasonal cycle as a result of seasonal variations in runoff, evaporation, and other water budget components. Significant changes have been observed in these seasonal lake level cycles since 1860, particularly for Lakes Erie and Ontario, which are rising and falling earlier in...

1] The export of nitrate by the Mississippi River to the Gulf of Mexico has tripled since the 1950s primarily due to an increase in agricultural fertilizer application and hydrological changes. Here we have adapted two physically based models, the Integrated Biosphere Simulator (IBIS) terrestrial ecosystem model and the Hydrological Routing Algorit...

Numerous long-term trends in the rate-of-change in monthly mean Great Lakes water levels are identified for the period 1860 to 1998. Statistically significant trends are found for 2, 4, 5, and 7 months of the year for Lakes Superior, Michigan-Huron, Erie, and Ontario, respectively. Many of the trends translate into large changes in net water flux (...

The spatial and temporal distribution of groundwater recharge depends on the complex interaction of hydrologic, atmospheric, pedologic, vegetative, and geologic processes, making it one of the most difficult and uncertain hydrologic parameters to quantify, yet understanding its distribution is a basic prerequisite for effective groundwater resource...

While a new class of Dynamic Global Ecosystem Models (DGEMs) has emerged in the past few years as an important tool for describing global biogeochemical cycles and atmosphere-biosphere interactions, these models are still largely untested. Here we analyze the behavior of a new DGEM and compare the results to global-scale observations of water balan...

The land surface water balance of the continental United States is analyzed from 1963 to 1995 using a terrestrial biosphere model (IBIS), reanalysis data from NCEP/NCAR, a hydrologic routing model (HYDRA), and numerous observational data sets. Emphasis is placed on evaluating the performance of IBIS and the reanalysis, particularly over the central...

1. Within a region with common climatic conditions, lake thermal variables should exhibit coherent variability patterns to the extent to which they are not influenced by lake specific features such as morphometry and water clarity. We tested the degree of temporal coherence in interannual variability for climatic variables (air temperature and sola...

While a new class of Dynamic Global Ecosystem Models (DGEMs) has emerged in the past few years as an important tool for describing global biogeochemical cycles and atmosphere-biosphere interactions, these models are still largely untested. Here we analyze the behavior of a new DGEM and compare the results to global-scale observations of water balan...

The observed large-scale circulation mechanisms associated with summertime precipitation variability over South America are investigated. Particular attention is paid to the Altiplano where a close relationship has been observed between rainfall and the position and intensity of the Bolivian high. Empirical orthogonal function (EOF), correlation, a...

Lake ice phenology parameters (dates of ice onset and thaw) provide an integrative climatic description of autumn td springtime conditions. Interannual variations in lake ice duration and thickness allow estimates of local climatic variability. In addition, long-term changes in lake ice phenology may provide a robust indication of climatic change....

The climatological structure in the upper-tropospheric summertime circulation over South America