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At least 667 records · Page 37Linked to original sources
USGS2016

Spatial and temporal patterns of dissolved organic matter quantity and quality in the Mississippi River Basin, 1997–2013

Recent studies have found insignificant or decreasing trends in time-series dissolved organic carbon (DOC) datasets, questioning the assumption that long-term DOC concentrations in surface waters are increasing in response to anthropogenic forcing, including climate change, land use, and atmospheric acid deposition. We used the weighted regressions on time, discharge, and season (WRTDS) model to estimate annual flow-normalized concentrations and fluxes to determine if changes in DOC quantity and quality signal anthropogenic forcing at 10 locations in the Mississippi River Basin. Despite increases in agriculture and urban development throughout the basin, net increases in DOC concentration and flux were significant at only 3 of 10 sites from 1997 to 2013 and ranged between −3.5% to +18% and −0.1 to 19%, respectively. Positive shifts in DOC quality, characterized by increasing specific ultraviolet absorbance at 254 nm, ranged between +8% and +45%, but only occurred at one of the sites with significant DOC quantity increases. Basinwide reductions in atmospheric sulfate deposition did not result in large increases in DOC either, likely because of the high buffering capacity of the soil. Hydroclimatic factors including annual discharge, precipitation, and temperature did not significantly change during the 17-year timespan of this study, which contrasts with results from previous studies showing significant increases in precipitation and discharge over a century time scale. Our study also contrasts with those from smaller catchments, which have shown stronger DOC responses to climate, land use, and acidic deposition. This temporal and spatial analysis indicated that there was a potential change in DOC sources in the Mississippi River Basin between 1997 and 2013. However, the overall magnitude of DOC trends was not large, and the pattern in quantity and quality increases for the 10 study sites was not consistent throughout the basin.

Hydrological Processes↗
USGS1995

Continental climate response to orbital forcing from biogenic silica records in Lake Baikal

CHANGES in insolation caused by periodic changes in the Earth's orbital parameters provide the primary forcing for global ice ages1-6. But it is not clear to what extent the climates in continental interiors are controlled directly by regional variations in insolation and to what extent they are driven instead by the highly nonlinear response of the oceans and ice sheets. Here we investigate this question using the record of biogenic silica in Lake Baikal as a proxy for climate change in this high-latitude mid-continental region. We find a good correlation between this record and that of marine oxygen isotopes4. Over the past 250 kyr the Baikal record exhibits both a strongly nonlinear component (manifested in a 100-kyr periodicity) and weaker direct-insolation components (manifested in the 41-kyr (obliquity) and 23- and 19-kyr (precession) orbital cycles). These results show that even though extreme continental climates such as this are influenced directly by insolation variations, they are dominated by the nonlinear rhythm of the oceans and ice sheets.

Lake Baikal↗
USGS2007

Monitoring alpine plants for climate change: The North American GLORIA Project

Alpine Environments Globally, alpine environments are hotspots of biodiversity, often harboring higher diversity of plant species than corresponding areas at lower elevations. These regions are also likely to experience more severe and rapid change in climate than lowlands under conditions of anthropogenic warming (Theurillat & Guisan 2001; Halloy & Mark 2003; Pickering & Armstrong 2003). Such climatic effects are already being documented by instrumental monitoring in the few places in western North America where long-term climate stations are available at high elevations. New sites are being planned (see GCOS article, pg 15). Climate Change is augmenting concern for alpine vegetation because available habitat diminishes at increasingly higher elevations. This creates an “elevational squeeze,” whereby the geometry of mountain peaks means that escape routes to cooler environments uphill are dead ends for migrating alpine species. While monitoring and modeling efforts have begun to elucidate climate of alpine environments in North America, very little is known about corresponding responses of alpine plant species to changing climate. Indeed, for many mountain regions in the West, little information exists even about alpine plant distribution and abundance.

Mountain Views↗
USGS1990

Neogene paleoceanographic events recorded in an active-margin setting: Humboldt basin, California

Recognition of North Pacific paleoceanographic events in the marginal Humboldt (Eel River) basin of northern California enables correlation of stratigraphic sections and development of a chronostratigraphy. Paleoclimatically related coiling shifts in Neogloboquadrina pachyderma (Ehrenberg) and benthic foraminiferal datums form the basis of the chronostratigraphy. Benthic foraminiferal datums are defined by the occurrence of selected benthic species and abundance maxima of benthic biofacies. The compiled chronostratigraphy is used to refine reconstructions of the depositional history of Humboldt basin. Paleoceanographic events, recognized by the distribution of benthic foraminiferal biofacies, are used to infer paleoceanographic history along the northeastern Pacific margin. The similarity in coiling curves of N. pachyderma from the marine sequence at DSDP Site 173 and the coastal Centerville Beach section of Humboldt basin and at other independently dated sites along the northeastern Pacific margin demonstrates that matching records of climatic oscillations is a reliable method of correlating marine sequences. Benthic fauna from the Centerville Beach section vary in phase with climatically related coiling shifts in N. pachyderma . In particular these data show an increase in displaced neritic fauna during inferred warm intervals and resurgence of deeper bathyal fauna during inferred cool events. Similar data are observed from the inland Eel River section, demonstrating that benthic foraminiferal trends recognized at Centerville Beach can be identified elsewhere in Humboldt basin. This in-phase benthic response to climatic fluctuations probably results from changes in vertical depth range of many benthic species in response to paleoclimatically related vertical changes in water-mass position. Depositional histories reconstructed for two key sites in southern Humboldt basin indicate low rates of sediment accumulation during early basin filling with hemipelagic sediments. Initiation of turbidite sedimentation in the early Pliocene resulted in a sharp increase in rate of sediment accumulation. This increase in rate of sediment accumulation is partially a response to tectonic uplift in the northern Coast Ranges and may be an effect of realignment of motion between the Pacific and North American plates at about this time. The inland site shoaled more rapidly during turbidite sedimentation as a result of a higher rate of sediment accumulation. The rate of sediment accumulation increased again at this site in the late Pliocene during deposition of shelf and nearshore facies. The Eel River region subsided concurrent with deposition of these shallow-water deposits.

Palaeogeography, Palaeoclimatology, Palaeoecology↗
USGS2024

Peak streamflow trends and their relation to changes in climate in Illinois, Iowa, Michigan, Minnesota, Missouri, Montana, North Dakota, South Dakota, and Wisconsin

Flood-frequency analysis, also called peak-flow frequency or flood-flow frequency analysis, is essential to water resources management applications including critical structure design and floodplain mapping. Federal guidelines for doing flood-frequency analyses are presented in a U.S. Geological Survey Techniques and Methods report known as Bulletin 17C. A basic assumption within Bulletin 17C is that for drainage basins without major hydrologic alterations, statistical properties of the distribution of annual peak streamflows (peak flows) are stationary; that is, the mean, variance, and skew are constant. The stationarity assumption has been widely accepted within the flood-frequency community; however, a better understanding of long-term climatic persistence and concerns about potential climate change and land-use change has caused a reexamination of the stationarity assumption. This work is part of that reexamination. The stationarity assumption is a concern because flood-frequency analyses that do not incorporate observed trends and abrupt changes may result in a poor representation of the true flood risk. Bulletin 17C does not offer guidance for incorporating nonstationarities when estimating floods, and it describes a need for studies that incorporate changing climate or basin characteristics. In response to this need and a history of concern regarding nonstationarity peak flows in the region, this study was done to assess potential nonstationarity in peak flows in the north-central United States. This report summarizes the methods used to detect hydroclimatic changes in peak-flow data in the study region. Four periods were selected for analysis of peak flow, daily streamflow, and climate data. The periods are (1) a 100-year period, 1921–2020; (2) a 75-year period, 1946–2020; (3) a 50-year period, 1971–2020; and (4) a 30-year period, 1991–2020. The starting point for these analyses was the initial data analysis of peak flow described in Bulletin 17C, which includes plotting the peak flow and checking for autocorrelation, monotonic trends, and changes points. Analyses were added to examine additional features in the data. Results are provided in a U.S. Geological Survey data release. The study limitations are documented for users of the results.

Scientific Investigations Report↗
USGS1998

Drought-induced shift of a forest-woodland ecotone: Rapid landscape response to climate variation

In coming decades, global climate changes are expected to produce large shifts in vegetation distributions at unprecedented rates. These shifts are expected to be most rapid and extreme at ecotones, the boundaries between ecosystems, particularly those in semiarid landscapes. However, current models do not adequately provide for such rapid effects—particularly those caused by mortality—largely because of the lack of data from field studies. Here we report the most rapid landscape-scale shift of a woody ecotone ever documented: in northern New Mexico in the 1950s, the ecotone between semiarid ponderosa pine forest and piñon–juniper woodland shifted extensively (2 km or more) and rapidly (<5 years) through mortality of ponderosa pines in response to a severe drought. This shift has persisted for 40 years. Forest patches within the shift zone became much more fragmented, and soil erosion greatly accelerated. The rapidity and the complex dynamics of the persistent shift point to the need to represent more accurately these dynamics, especially the mortality factor, in assessments of the effects of climate change.

Proceedings of the National Academy of Sciences of↗
USGS2015

Impacts of climate change on land-use and wetland productivity in the Prairie Pothole Region of North America

Wetland productivity in the Prairie Pothole Region (PPR) of North America is closely linked to climate. A warmer and drier climate, as predicted, will negatively affect the productivity of PPR wetlands and the services they provide. The effect of climate change on wetland productivity, however, will not only depend on natural processes (e.g., evapotranspiration), but also on human responses. Agricultural land use, the predominant use in the PPR, is unlikely to remain static as climate change affects crop yields and prices. Land use in uplands surrounding wetlands will further affect wetland water budgets and hence wetland productivity. The net impact of climate change on wetland productivity will therefore depend on both the direct effects of climate change on wetlands and the indirect effects on upland land use. We examine the effect of climate change and land-use response on semipermanent wetland productivity by combining an economic model of agricultural land-use change with an ecological model of wetland dynamics. Our results suggest that the climate change scenarios evaluated are likely to have profound effects on land use in the North and South Dakota PPR, with wheat displacing other crops and pasture. The combined pressure of land-use and climate change significantly reduces wetland productivity. In a climate scenario with a +4 °C increase in temperature, our model predicts that almost the entire region may lack the wetland productivity necessary to support wetland-dependent species.

North Dakota, South Dakota↗
USGS2011

Global patterns of phytoplankton dynamics in coastal ecosystems

Scientific Committee on Ocean Research Working Group 137 Meeting; Hangzhou, China, 17-21 October 2010; Phytoplankton biomass and community structure have undergone dramatic changes in coastal ecosystems over the past several decades in response to climate variability and human disturbance. These changes have short- and long-term impacts on global carbon and nutrient cycling, food web structure and productivity, and coastal ecosystem services. There is a need to identify the underlying processes and measure the rates at which they alter coastal ecosystems on a global scale. Hence, the Scientific Committee on Ocean Research (SCOR) formed Working Group 137 (WG 137), "Global Patterns of Phytoplankton Dynamics in Coastal Ecosystems: A Comparative Analysis of Time Series Observations" (http://wg137.net/). This group evolved from a 2007 AGU-sponsored Chapman Conference entitled "Long Time-Series Observations in Coastal Ecosystems: Comparative Analyses of Phytoplankton Dynamics on Regional to Global Scales.".

Conference Paper↗
USGS2020

Soil respiration response to rainfall modulated by plant phenology in a montane meadow, East River, Colorado, USA

Soil respiration is a primary component of the terrestrial carbon cycle. However, predicting the response of soil respiration to climate change remains a challenge due to the complex interactions between environmental drivers, especially plant phenology, temperature, and soil moisture. In this study, we use a 1‐D diffusion‐reaction model to calculate depth‐resolved CO 2 production rates from soil CO 2 concentrations and surface efflux observations in a subalpine meadow in the East River watershed, CO. Modeled rates are compared to in situ soil temperature and moisture conditions and MODIS satellite enhanced vegetation index (EVI) representing plant phenology across three hydrologically distinct growing seasons from 2016–2018. While soil respiration correlated with temperature on diel timescales ( p < 0.05), seasonal variability was dominated by soil moisture and plant phenology ( p < 0.05). We observed significant respiration increases in response to precipitation events; however, magnitude and duration were significantly higher in 2017 than 2016 despite similar wetting characteristics. Based on MODIS EVI, we suggest that the respiration response to rainfall is controlled by plant phenology, which in turn reflects the capacity of plants to respond to precipitation via increased photosynthesis and autotrophic respiration, behavior that is not captured in typical soil respiration pulse models. Projected changes in montane climate such as earlier snowmelt and prolonged fore‐summer drought may decrease soil respiration fluxes by decreasing the overlap between peak productivity and the summer monsoon. Finally, we observed significant late season CO 2 fluxes from the deep subsoil (>165 cm) that support growing evidence for the importance of subsoil processes in driving integrated respiration fluxes.

Colorado↗
USGS2019

Winter climate change and the poleward range expansion of a tropical invasive tree (Brazilian pepper ‐ Shinus terebinthifolius)

Winter climate change is expected to lead to the tropicalization of temperate ecosystems, where tropical species expand poleward in response to a decrease in the intensity and duration of winter temperature extremes (i.e., freeze events). In the southeastern United States, freezing temperatures control the northern range limits of many invasive non‐native species. Here, we examine the influence of freezing temperatures and winter climate change on the northern range limits of an invasive non‐native tree — Schinus terebenthifolius (Brazilian pepper). Since introduction in the 1800s, Brazilian pepper has invaded ecosystems throughout south and central Florida to become the state's most widespread non‐native plant species. Although Brazilian pepper is sensitive to freezing temperatures, temperature controls on its northern distribution have not been adequately quantified. We used temperature and plant occurrence data to quantify the sensitivity of Brazilian pepper to freezing temperatures. Then, we examined the potential for range expansion under three alternative future climate scenarios (+2°C, +4°C, and +6°C). Our analyses identify a strong nonlinear sigmoidal relationship between minimum temperature and Brazilian pepper presence, with a discrete threshold temperature occurring near ‐11°C. Our future scenario analyses indicate that, in response to warming winter temperatures, Brazilian pepper is expected to expand northward and transform ecosystems in north Florida and across much of the Gulf of Mexico and south Atlantic coasts of the United States. These results underscore the importance of early detection and rapid response efforts to identify and manage the northward invasion of Brazilian pepper in response to climate change. Looking more broadly, our work highlights the need to anticipate and prepare for the tropicalization of temperate ecosystems by tropical invasive species.

Florida, Georgia, South Carolina↗
USGS2016

Detecting failure of climate predictions

The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty 1 , 2 . Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies 3 . Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

Nature Climate Change↗
USGS2020

Parsing complex terrain controls on mountain glacier response to climate forcing

Glaciers are a key indicator of changing climate in the high mountain landscape. Glacier variations across a mountain range are ultimately driven by regional climate forcing. However, changes also reflect local, topographically driven processes such as snow avalanching, snow wind-drifting, and radiation shading as well as the initial glacier conditions such as hypsometry and ice thickness. Here we assess the role of these various terrain influences on change to Little Ice Age (LIA) glaciers in Glacier National Park, U.S.A . With available data for LIA and modern glacier areas, we estimate glacier volumes using simple ice flow assumptions, and topographically driven processes using terrain proxies. At the LIA glacial maxima there were 82 glaciers larger than 0.1 km 2 ranging from 0.11 to 4.97 km 2 . Over the course of the 20 th century, every single LIA glacier decreased in area and 60% (49 glaciers) diminished to below the 0.1 km 2 threshold. Glaciers with large initial area (>1.5 km 2 ) at the end of LIA persisted. Within the intermediate size class (0.5 km 2 < area < 1.5 km 2 ), LIA glacier persistence is poorly explained by initial glacier volume, ice thickness, or elevation. Instead, wind exposure is an important explanatory factor. Our analysis demonstrates the complex response of cirque glaciers to post-LIA climate change in this region: individual glaciers have not necessarily undergone equivalent and synchronous change. Nevertheless, that all glaciers in this mountain range experienced retreat demonstrates that local processes mediated adjustments of some glaciers, but completely decoupled none from the regional climate forcing.

Montana↗
USGS2024

Why do avian responses to change in Arctic green-up vary?

Global climate change has altered the timing of seasonal events (i.e., phenology) for a diverse range of biota. Within and among species, however, the degree to which alterations in phenology match climate variability differ substantially. To better understand factors driving these differences, we evaluated variation in timing of nesting of eight Arctic-breeding shorebird species at 18 sites over a 23-year period. We used the Normalized Difference Vegetation Index as a proxy to determine the start of spring (SOS) growing season and quantified relationships between SOS and nest initiation dates as a measure of phenological responsiveness. Among species, we tested four life history traits (migration distance, seasonal timing of breeding, female body mass, expected female reproductive effort) as species-level predictors of responsiveness. For one species (Semipalmated Sandpiper), we also evaluated whether responsiveness varied across sites. Although no species in our study completely tracked annual variation in SOS, phenological responses were strongest for Western Sandpipers, Pectoral Sandpipers, and Red Phalaropes. Migration distance was the strongest additional predictor of responsiveness, with longer-distance migrant species generally tracking variation in SOS more closely than species that migrate shorter distances. Semipalmated Sandpipers are a widely distributed species, but adjustments in timing of nesting relative to variability in SOS did not vary across sites, suggesting that different breeding populations of this species were equally responsive to climate cues despite differing migration strategies. Our results unexpectedly show that long-distance migrants are more sensitive to local environmental conditions, which may help them to adapt to ongoing changes in climate.

Article↗
USGS2013

Response of global soil consumption of atmospheric methane to changes in atmospheric climate and nitrogen deposition

Soil consumption of atmospheric methane plays an important secondary role in regulating the atmospheric CH 4 budget, next to the dominant loss mechanism involving reaction with the hydroxyl radical (OH). Here we used a process-based biogeochemistry model to quantify soil consumption during the 20th and 21st centuries. We estimated that global soils consumed 32–36 Tg CH 4 yr −1 during the 1990s. Natural ecosystems accounted for 84% of the total consumption, and agricultural ecosystems only consumed 5 Tg CH 4 yr −1 in our estimations. During the twentieth century, the consumption rates increased at 0.03–0.20 Tg CH 4 yr −2 with seasonal amplitudes increasing from 1.44 to 3.13 Tg CH 4 month −1 . Deserts, shrublands, and xeric woodlands were the largest sinks. Atmospheric CH 4 concentrations and soil moisture exerted significant effects on the soil consumption while nitrogen deposition had a moderate effect. During the 21st century, the consumption is predicted to increase at 0.05-1.0 Tg CH 4 yr −2 , and total consumption will reach 45–140 Tg CH 4 yr −1 at the end of the 2090s, varying under different future climate scenarios. Dry areas will persist as sinks, boreal ecosystems will become stronger sinks, mainly due to increasing soil temperatures. Nitrogen deposition will modestly reduce the future sink strength at the global scale. When we incorporated the estimated global soil consumption into our chemical transport model simulations, we found that nitrogen deposition suppressed the total methane sink by 26 Tg during the period 1998–2004, resulting in 6.6 ppb higher atmospheric CH 4 mixing ratios compared to without considering nitrogen deposition effects. On average, a cumulative increase of every 1 Tg soil CH 4 consumption decreased atmospheric CH 4 mixing ratios by 0.26 ppb during the period 1998–2004.

Global Biogeochemical Cycles↗
USGS2014

Delivering climate science about the Nation's fish, wildlife, and ecosystems: the U.S. Geological Survey National Climate Change and Wildlife Science Center

Changes to the Earth’s climate—temperature, precipitation, and other climate variables—pose significant challenges to our Nation’s natural resources. Managers of land, water, and living resources require an understanding of the impacts of climate change—which exacerbate ongoing stresses such as habitat alteration and invasive species—in order to design effective response strategies. In 2008, Congress created the National Climate Change and Wildlife Science Center (NCCWSC) within the U.S. Geological Survey (USGS). The center was formed to address environmental challenges resulting from climate and land-use change and to provide natural resource managers with rigorous scientific information and effective tools for decision making. Located at the USGS National Headquarters in Reston, Virginia, the NCCWSC has established eight regional Department of the Interior (DOI) Climate Science Centers (CSCs) and has invested over $93 million (through fiscal year 2013) in cutting-edge climate change research.

Fact Sheet↗
USGS2023

Climate change and pulse migration: Intermittent Chugach Inuit occupation of glacial fiords on the Kenai Coast, Alaska

For millennia, Inuit peoples of the Arctic and Subarctic have been challenged by the impacts of climate change on the abundance of key subsistence species. Responses to climate-induced declines in animal populations included switching to alternative food sources and/or migrating to regions of greater availability. We examine these dynamics for the Chugach Inuit (Sugpiat) people of southern coastal Alaska by synthesizing a large body of evidence from archeological sites, including radiocarbon dates and archaeofaunal assemblages, and by applying contemporary knowledge of glaciomarine ecosystems, spatial patterns of resource richness, and ocean-climate induced regime shifts in the Gulf of Alaska. We hypothesize that Chugach groups migrated from Cook Inlet and Prince William Sound to the Kenai Peninsula during periods of low sea surface temperatures (SSTs) to harvest harbor seals, which were seasonally aggregated near tidewater glaciers during pupping season, as well as piscivorous seabirds, Pacific cod, and other species that thrive under cool ocean conditions. During warming phases, the Chugach returned to Cook Inlet and Prince William Sound to fish for salmon and other species that abound during higher SSTs. Drivers of this coupled human-natural system of repeated (pulse) migration include the Pacific Decadal Oscillation (PDO), the dominant pattern of sea surface temperatures in the North Pacific that has been shown to generate step-like regime shifts in the marine food web; and coastal glaciers that structure the functioning of fiord ecosystems and support high levels of biological productivity. The culturally-constructed Chugach niche in the glaciomarine habitat of the Gulf of Alaska was based on intergenerationally transmitted ecological knowledge that enabled a resilient, mobile response to climate and resource variation.

Alaska↗
USGS2020

Integrating the evidence for a terrestrial carbon sink caused by increasing atmospheric CO2

Atmospheric carbon dioxide concentration ([CO 2 ]) is increasing, which increases leaf‐scale photosynthesis and intrinsic water‐use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO 2 ] increase and thus climate change. However, ecosystem CO 2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO 2 ]‐driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO 2 ] (iCO 2 ) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre‐industrial times. Established theory, supported by experiments, indicates that iCO 2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO 2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO 2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO 2 , albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.

New Phytologist↗
USGS2019

Historical changes in New York State streamflow: Attribution of temporal shifts and spatial patterns from 1961 to 2016

To better understand the effects of climate change on streamflow, the hydrologic response to both temperature and precipitation needs to be examined at the mesoscale. New York State provides a hydrologically diverse mesoscale region, where sub-regional clusters of watersheds may respond differently to changes in temperature and in seasonal precipitation rates. Connections between streamflow and climate were examined for 97 gaging stations across the state and surrounding areas, for a historical period of 56 years of daily average streamflow. Gages were grouped into clusters if their mean annual discharge rates were strongly correlated to one another. Within each cluster, sharp temporal changes in discharge, or change points, were identified. These change points clustered both spatially and by flow regime, with low, medium, and high flows increasing around 1970 for much of the state consistent with other studies in the region. A step increase in Catskill low flows in 2003 coincides with increases in summer precipitation, and is consistent with a positive correlation between summer precipitation and annual low flows. Our results support previous studies that have shown that streamflow at this mesoscale is strongly tied to precipitation, and the strength of that connection is modulated by land cover, geographic position, and seasonal moisture conditions. Across the state, the winter-spring center of volume date has moved earlier along with increasing January streamflow rates, the result of warmer winter temperatures and an increased proportion of precipitation as rain. The transition to a post-1970s pluvial period also coincided with more frequent peak over threshold flows statewide, and this wetter period has continued to the present day.

New York↗