Changes in the phase of the annual cycle of surface temperature

Stine, A.; Huybers, Peter; Fung, Inez

doi:10.1038/nature07675

Cited by 242 publications

(319 citation statements)

References 47 publications

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“…3B). A steady lengthening of the growing season has been documented worldwide (7), and even a shift in the seasonal phase of surface temperatures has been detected (28). Growing degree days correlate with the speed of forest recovery from pasture in the Amazon (9,29) and increased plant growth in boreal forests (11,25).…”

Section: Resultsmentioning

confidence: 99%

Evidence for a recent increase in forest growth

McMahon

Parker

Miller

2010

Proc. Natl. Acad. Sci. U.S.A.

351

274

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Forests and their soils contain the majority of the earth's terrestrial carbon stocks. Changes in patterns of tree growth can have a huge impact on atmospheric cycles, biogeochemical cycles, climate change, and biodiversity. Recent studies have shown increases in biomass across many forest types. This increase has been attributed to climate change. However, without knowing the disturbance history of a forest, growth could also be caused by normal recovery from unknown disturbances. Using a unique dataset of tree biomass collected over the past 22 years from 55 temperate forest plots with known land-use histories and stand ages ranging from 5 to 250 years, we found that recent biomass accumulation greatly exceeded the expected growth caused by natural recovery. We have also collected over 100 years of local weather measurements and 17 years of on-site atmospheric CO 2 measurements that show consistent increases in line with globally observed climate-change patterns. Combined, these observations show that changes in temperature and CO 2 that have been observed worldwide can fundamentally alter the rate of critical natural processes, which is predicted by biogeochemical models. Identifying this rate change is important to research on the current state of carbon stocks and the fluxes that influence how carbon moves between storage and the atmosphere. These results signal a pressing need to better understand the changes in growth rates in forest systems, which influence current and future states of the atmosphere and biosphere. T he movement of carbon in our atmosphere, oceans, and terrestrial ecosystems is critical to predicting how climate change may influence the natural systems on which humans rely (1-4). Changes in ecosystems can, in turn, feed back into global atmospheric cycles through evapotranspiration, net ecosystem CO 2 exchange, and surface albedo and roughness, which complicates predictions about future climate states (1, 5-7). Key evidence that global changes may affect the functioning of forests is shown in changes in forest biomass over time, which can have important implications for whether or not forests accumulate biomass at a rate that would alter current trends of atmospheric carbon cycling (8).In densely forested regions across the globe, forests can recover rapidly from agricultural fields, logged stands, or areas cleared because of natural disturbances as long as remnant patches or seed banks remain. Across forest types, the period of recovery consists of a rapid rise in above-ground biomass (AGB) followed by a leveling off as the canopy fills in and biomass shifts from the sum of many small stems to fewer, larger canopy trees. The rate and asymptote of this pattern of biomass recovery can differ across stands because of nutrient availability and species composition or can differ between regions because of climate and disturbance regimens; however, the functional form of this response remains similar across forest types and regions (9, 10).There are indications that forest biomass accumulation...

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Section: Resultsmentioning

confidence: 99%

Evidence for a recent increase in forest growth

McMahon

Parker

Miller

2010

Proc. Natl. Acad. Sci. U.S.A.

351

274

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“…We find that the TOA thermal emission over sea ice exhibits large seasonal temperature variations that are approximately in phase with the forcing, while that over ocean exhibits muted seasonal variations with significant phase lag. As noted by Stine et al (2009), mixing these signals results in a low-amplitude, small-offset response, because the large amplitude component (solid surfaces) dominate the offset. Since the land in our simulation is mostly tropical, its TOA thermal emission peaks during the relatively dry winter months, while the high surface temperature is masked by overlying clouds and humidity in the summer.…”

Section: Obliquity Seasonsmentioning

confidence: 99%

Thermal Phases of Earth-Like Planets: Estimating Thermal Inertia From Eccentricity, Obliquity, and Diurnal Forcing

Cowan

Voigt

Abbot

2012

ApJ

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In order to understand the climate on terrestrial planets orbiting nearby Sun-like stars, one would like to know their thermal inertia. We use a global climate model to simulate the thermal phase variations of Earth analogs and test whether these data could distinguish between planets with different heat storage and heat transport characteristics. In particular, we consider a temperate climate with polar ice caps (like the modern Earth) and a snowball state where the oceans are globally covered in ice. We first quantitatively study the periodic radiative forcing from, and climatic response to, rotation, obliquity, and eccentricity. Orbital eccentricity and seasonal changes in albedo cause variations in the global-mean absorbed flux. The responses of the two climates to these global seasons indicate that the temperate planet has 3× the bulk heat capacity of the snowball planet due to the presence of liquid water oceans. The obliquity seasons in the temperate simulation are weaker than one would expect based on thermal inertia alone; this is due to cross-equatorial oceanic and atmospheric energy transport. Thermal inertia and cross-equatorial heat transport have qualitatively different effects on obliquity seasons, insofar as heat transport tends to reduce seasonal amplitude without inducing a phase lag. For an Earth-like planet, however, this effect is masked by the mixing of signals from low thermal inertia regions (sea ice and land) with that from high thermal inertia regions (oceans), which also produces a damped response with small phase lag. We then simulate thermal light curves as they would appear to a high-contrast imaging mission (TPF-I/Darwin). In order of importance to the present simulations, which use modern-Earth orbital parameters, the three drivers of thermal phase variations are (1) obliquity seasons, (2) diurnal cycle, and (3) global seasons. Obliquity seasons are the dominant source of phase variations for most viewing angles. A pole-on observer would measure peak-to-trough amplitudes of 13% and 47% for the temperate and snowball climates, respectively. Diurnal heating is important for equatorial observers (∼5% phase variations), because the obliquity effects cancel to first order from that vantage. Finally, we compare the prospects of optical versus thermal direct imaging missions for constraining the climate on exoplanets and conclude that while zero-and one-dimensional models are best served by thermal measurements, second-order models accounting for seasons and planetary thermal inertia would require both optical and thermal observations.

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“…Nevertheless, the understanding of seasonal shifts and spatial patterns of global temperature trends over time, however, has been restricted by limitations in observations and associated scaling. Mechanisms by which warming through increasing atmospheric CO 2 concentrations may cause shifts in the timing, duration, and intensity of the annual temperature cycle are not captured by current global models [10].…”

Section: Introductionmentioning

confidence: 99%

“…Stine et al [10] found that the temperature cycle advanced by 1.7 days between 1954 and 2007 over extra-tropical land, based on an averaged yearly shifts between monthly values of local solar insolation and surface temperature. Thomson [6] discovered a coherency between the average change in phase and the logarithm of atmospheric CO 2 concentration for Central England.…”

Section: Introductionmentioning

confidence: 99%

“…Other regions, including parts of the northern Atlantic, the southern oceans, and parts of Antarctica actually cooled [1][2][3][4][5]. In addition to warming, or changes in the temperature amplitude, changes in the phase of annual cycle of air temperature have been shown in analyses of several datasets using a variety of methods [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Distinct Global Patterns of Strong Positive and Negative Shifts of Seasons over the Last 6 Decades

Schmidt¹,

Law²,

Hanson³

et al. 2012

ACS

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Alterations of annual temperature cycles have profound implications on how the planet responds to global climate change. In this study, a high resolution global analysis of temperature cycle shifts and their development over time is presented. We show that over the last 63 years, phase shifts in the annual near surface temperature cycle exhibit large spatiotemporal variability. The calculated phase shifts comprise earlier onsets of seasons as well as delays with similar frequencies, depending on location. From 1978 to 2010 Eastern Europe experienced an advanced annual cycle of near-surface temperature of 3.2 days while Eastern Australia shows an opposite shift towards later seasons of 3.5 days in comparison to the preceding 30-year period from 1948 to 1977. The largest phase shifts of -5.5 days toward earlier seasons over land were found in Belarus and Northwest Russia. For the first time the developments of seasonal temperature shifts were generalized for large areas by using self-organizing feature map neural networks resulting into 4 significant global trends. The temperature phase shifts are also shown to have strong correlations with the timing of shrub foliation observed at 57 phenological stations across the USA. The findings have far-reaching, yet regionally distinct consequences on agriculture, animal life cycles, plant phenology, and regional weather phenomena that change with annual temperature cycles.

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Changes in the phase of the annual cycle of surface temperature

Cited by 242 publications

References 47 publications

Evidence for a recent increase in forest growth

Evidence for a recent increase in forest growth

Thermal Phases of Earth-Like Planets: Estimating Thermal Inertia From Eccentricity, Obliquity, and Diurnal Forcing

Distinct Global Patterns of Strong Positive and Negative Shifts of Seasons over the Last 6 Decades

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