Identifying anomalously early spring onsets in the CESM large ensemble project

Labe, Zachary M.; Ault, Toby R.; Zurita-Milla, R.

doi:10.1007/s00382-016-3313-2

Cited by 25 publications

(17 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our analysis indicated that snow melt as indicated by changes in SWE and depth were most sensitive to winter coldness. Moving toward warmer winters (Hayhoe et al ., ) and earlier spring onset (Labe et al ., ) in the future, we anticipate longer lags between when air temperature increases and the snowpack responds, due in part to the fact that the transition in air temperature will happen earlier in the year when there is less incoming solar radiation. However, even though the lag between the increase in air temperature and the snow‐free date may be longer, we will still expect snow‐free days to occur earlier in the year, exposing the underlying ground and resulting in more overall energy absorption into the system as compared to colder years.…”

Section: Discussionmentioning

confidence: 99%

A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags

Contosta

Adolph

Burchsted

et al. 2016

Global Change Biology

View full text Add to dashboard Cite

Climate change is altering the timing and duration of the vernal window, a period that marks the end of winter and the start of the growing season when rapid transitions in ecosystem energy, water, nutrient, and carbon dynamics take place. Research on this period typically captures only a portion of the ecosystem in transition and focuses largely on the dates by which the system wakes up. Previous work has not addressed lags between transitions that represent delays in energy, water, nutrient, and carbon flows. The objectives of this study were to establish the sequence of physical and biogeochemical transitions and lags during the vernal window period and to understand how climate change may alter them. We synthesized observations from a statewide sensor network in New Hampshire, USA, that concurrently monitored climate, snow, soils, and streams over a three-year period and supplemented these observations with climate reanalysis data, snow data assimilation model output, and satellite spectral data. We found that some of the transitions that occurred within the vernal window were sequential, with air temperatures warming prior to snow melt, which preceded forest canopy closure. Other transitions were simultaneous with one another and had zero-length lags, such as snowpack disappearance, rapid soil warming, and peak stream discharge. We modeled lags as a function of both winter coldness and snow depth, both of which are expected to decline with climate change. Warmer winters with less snow resulted in longer lags and a more protracted vernal window. This lengthening of individual lags and of the entire vernal window carries important consequences for the thermodynamics and biogeochemistry of ecosystems, both during the winter-to-spring transition and throughout the rest of the year.

show abstract

Section: Discussionmentioning

confidence: 99%

A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags

Contosta

Adolph

Burchsted

et al. 2016

Global Change Biology

View full text Add to dashboard Cite

show abstract

“…Insect seed predators (tephritid and agromyzid flies that are host-specific to Helianthella) and mutualist ants that collect extrafloral nectar from buds (Inouye & Taylor, 1979) may also be affected by loss of flower buds to frost. Furthermore, frost events are expected to increase in frequency under continued climate change (Ellwood, Temple, Primack, Bradley, & Davis, 2013;Labe, Ault, & Zurita-Milla, 2016), emphasizing the importance of further study on the ecological effects of frost in the context of climate change.…”

Section: Discussionmentioning

confidence: 99%

Reproductive losses due to climate change‐induced earlier flowering are not the primary threat to plant population viability in a perennial herb

et al. 2019

View full text Add to dashboard Cite

Despite a global footprint of shifts in flowering phenology in response to climate change, the reproductive consequences of these shifts are poorly understood. Furthermore, it is unknown whether altered flowering times affect plant population viability. We examine whether climate change‐induced earlier flowering has consequences for population persistence by incorporating reproductive losses from frost damage (a risk of early flowering) into population models of a subalpine sunflower (Helianthella quinquenervis). Using long‐term demographic data for three populations that span the species’ elevation range (8–15 years, depending on the population), we first examine how snowmelt date affects plant vital rates. To verify vital rate responses to snowmelt date experimentally, we manipulate snowmelt date with a snow removal experiment at one population. Finally, we construct stochastic population projection models and Life Table Response Experiments for each population. We find that populations decline (λs < 1) as snowmelt dates become earlier. Frost damage to flower buds, a consequence of climate change‐induced earlier flowering, does not contribute strongly to population declines. Instead, we find evidence that negative effects on survival, likely due to increased drought risk during longer growing seasons, drive projected population declines under earlier snowmelt dates. Synthesis. Shifts in flowering phenology are a conspicuous and important aspect of biological responses to climate change, but here we show that the phenology of reproductive events can be unreliable measures of threats to population persistence, even when earlier flowering is associated with substantial reproductive losses. Evidence for shifts in reproductive phenology, along with scarcer evidence that these shifts actually influence reproductive success, are valuable but can paint an incomplete and even misleading picture of plant population responses to climate change.

show abstract

“…To the best of our knowledge previous studies have not investigated the role of internal variability on seasonal cycle projections at either the global or regional scales. A recent exception is Labe et al (), who use a large ensemble of climate model simulations to investigate the role of internal variability in future projections of spring onsets over the continental United States and demonstrate a large projected increase in the likelihood of early springs.…”

Section: Introductionmentioning

confidence: 99%

The Role of Internal Variability in Twenty‐First‐Century Projections of the Seasonal Cycle of Northern Hemisphere Surface Temperature

Yettella

England

2018

JGR Atmospheres

View full text Add to dashboard Cite

The seasonal cycle is fundamental to the Earth's climate system, accounting for the vast majority of temperature variance. Understanding how the seasonal cycle will change in the future, and by when, is a key question with important implications. Here a 40-member initial condition climate model ensemble is used to investigate the influence of internal variability on the detection of changes in the amplitude and timing of the seasonal cycle of surface temperature over Northern Hemisphere land in response to increasing greenhouse gases. Internal variability renders the detection of these changes challenging; even by the mid-twenty-first century, small ensembles will be insufficient to separate the forced signals from internal variability over many continental regions in the Northern Hemisphere. Despite this, projected changes over Europe, North Africa, and Siberia are large and easily detectable, even in a single member. Specifically, amplitude increases over Europe and North Africa while it decreases over Siberia. On the other hand, the timing of the seasonal cycle is delayed over all three regions. It is found that these changes are remarkably robust across model ensembles from the Coupled Model Intercomparison Project phase 5 archive. To understand the mechanisms underlying these robust changes, a simple energy balance model is used to partition changes into contributions arising from changes in the physical parameters that control the seasonal cycle. It is found that future changes in the seasonal cycle over the three regions are most strongly controlled by changes in surface longwave and turbulent heat fluxes.

show abstract

Identifying anomalously early spring onsets in the CESM large ensemble project

Cited by 25 publications

References 39 publications

A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags

A longer vernal window: the role of winter coldness and snowpack in driving spring transitions and lags

Reproductive losses due to climate change‐induced earlier flowering are not the primary threat to plant population viability in a perennial herb

The Role of Internal Variability in Twenty‐First‐Century Projections of the Seasonal Cycle of Northern Hemisphere Surface Temperature

Contact Info

Product

Resources

About