An update on the hydroxyl airglow temperature record from the Auroral Station in Adventdalen, Svalbard (1980–2005)

2007 ◽  
Vol 85 (2) ◽  
pp. 143-151 ◽  
Author(s):  
M E Dyrland ◽  
F Sigernes
Keyword(s):  
Solar Rotation ◽  
Temperature Fluctuations ◽  
Winter Temperature ◽  
Temperature Record ◽  
Positive Temperature ◽  
Spectral Measurements ◽  
Daily Average ◽  
Winter Temperatures ◽  
Hydroxyl Airglow ◽  
Average Winter Temperature

This paper reports on the daily mesospheric winter temperature series derived from ground-based spectral measurements of the hydroxyl airglow layer from the Auroral Station in Adventdalen near Longyearbyen, Svalbard (78°N, 15°E). Temperature estimates from the four latest seasons (2001–2002 to 2004–2005) have been added to the series reported by Sigernes et al. J. Geophys. Res. 108(A9), 1342 (2003). Lomb–Scargle periodogram analyses were performed on both hourly and daily average temperatures to look for significant periods. From the daily means, ∼24 and ∼26 d oscillations that are consistent with a solar rotation modulation of the atmosphere were identified. Analyses of the hourly averaged data did not reveal any considerable diurnal and semidiurnal periods in the temperatures. The 2003–2004 mesopause winter was one of the warmest reported over Svalbard during the last 25 years. It is common to observe within a few days temperature fluctuations in the range 20–40 K. Some years show far less variation than others. The overall daily average winter temperature is 209 K. The annual mean winter temperatures show a slightly positive temperature trend (+0.2 ± 0.1 K/year), on the verge of being a statistically significant change in the winter mesospheric temperatures over Svalbard.PACS Nos.: 92.60.hc, 07.20.Dt, 93.30.Sq, 92.60.hw

scholarly journals How to correctly apply Gaussian statistics in a non-stationary climate?

2021 ◽  
Author(s):  
Reinhold Steinacker
Keyword(s):  
Time Series ◽  
Actual Data ◽  
Temperature Record ◽  
Positive Trend ◽  
Positive Temperature ◽  
Climatic Trend ◽  
Filter Methods ◽  
Periodic Time Series ◽  
Past Data

AbstractTime series with a significant trend, as is now being the case for the temperature in the course of climate change, need a careful approach for statistical evaluations. Climatological means and moments are usually taken from past data which means that the statistics does not fit to actual data anymore. Therefore, we need to determine the long-term trend before comparing actual data with the actual climate. This is not an easy task, because the determination of the signal—a climatic trend—is influenced by the random scatter of observed data. Different filter methods are tested upon their quality to obtain realistic smoothed trends of observed time series. A new method is proposed, which is based on a variational principle. It outperforms other conventional methods of smoothing, especially if periodic time series are processed. This new methodology is used to test, how extreme the temperature of 2018 in Vienna actually was. It is shown that the new annual temperature record of 2018 is not too extreme, if we consider the positive trend of the last decades. Also, the daily mean temperatures of 2018 are not found to be really extreme according to the present climate. The real extreme of the temperature record of Vienna—and many other places around the world—is the strongly increased positive temperature trend over the last years.

scholarly journals Mid-winter temperatures, not spring temperatures, predict breeding phenology in the European starling Sturnus vulgaris

2015 ◽  
Vol 2 (1) ◽  
pp. 140301 ◽  
Author(s):  
Tony D. Williams ◽  
Sophie Bourgeon ◽  
Allison Cornell ◽  
Laramie Ferguson ◽  
Melinda Fowler ◽  
...  
Keyword(s):  
Clutch Size ◽  
Prey Availability ◽  
Sturnus Vulgaris ◽  
Winter Temperature ◽  
Laying Date ◽  
Breeding Phenology ◽  
European Starlings ◽  
Winter Temperatures ◽  
Lag Times ◽  
High Degree

In many species, empirical data suggest that temperatures less than 1 month before breeding strongly influence laying date, consistent with predictions that short lag times between cue and response are more reliable, decreasing the chance of mismatch with prey. Here we show in European starlings ( Sturnus vulgaris ) that mid-winter temperature ca 50–90 days before laying (8 January–22 February) strongly ( r 2 = 0.89) predicts annual variation in laying date. Mid-winter temperature also correlated highly with relative clutch size: birds laid later, but laid larger clutches, in years when mid-winter temperatures were lower. Despite a high degree of breeding synchrony (mean laying date 5–13 April = ±4 days; 80% of nests laid within 4.8 days within year), European starlings show strong date-dependent variation in clutch size and productivity, but this appears to be mediated by a different temporal mechanism for integration of supplemental cue (temperature) information. We suggest the relationship between mid-winter temperature and breeding phenology might be indirect with both components correlating with a third factor: temperature-dependent development of the starling's insect (tipulid) prey. Mid-winter temperatures might set the trajectory of growth and final biomass of tipulid larvae, with this temperature cue providing starlings with information on breeding season prey availability (though exactly how remains unknown).

Delayed germination in seeds of Phacelia dubia var. dubia

1973 ◽  
Vol 51 (12) ◽  
pp. 2481-2486 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Seedling Establishment ◽  
Winter Temperature ◽  
Seed Crop ◽  
Temperature Conditions ◽  
Secondary Dormancy ◽  
Winter Temperatures ◽  
Winter Annual ◽  
Delayed Germination ◽  
Germinating Seeds

Not all seeds of a particular seed crop of the winter annual Phacelia dubia var. dubia germinate the first autumn after their dispersal in spring, and germination of a given seed crop is spread over several years. Nondormant seeds that do not germinate in autumn are induced into secondary dormancy by low winter temperatures and must afterripen again during summer before they are capable of germinating. Seeds that do not afterripen the first summer after dispersal are prevented from doing so until at least the next summer because winter temperature conditions prevent afterripening. These responses of the seeds to the environment insure that germination will occur only in autumn, the only season of the year that is suitable for seedling establishment and eventual completion of the life cycle.

Climatic determinants of introduced Sitka spruce in Hiiumaa Island, Estonia

2019 ◽  
Vol 25 (1) ◽  
pp. 161-167
Author(s):  
Alar Läänelaid ◽  
Samuli Helama
Keyword(s):  
Norway Spruce ◽  
Tree Ring ◽  
Sitka Spruce ◽  
Early Summer ◽  
Winter Temperature ◽  
Moisture Regime ◽  
Growth Responses ◽  
Growth Variability ◽  
Tree Ring Data ◽  
Winter Temperatures

Tree-ring records of Sitka spruce growing in Hiiumaa (Estonia) were investigated to illustrate their growth variability and its climatic determinants. A chronology comprising ring-width series of eight big individuals from the Suuremõisa forest park was correlated with local climatic records. The growth variability of this species introduced to Hiiumaa was statistically explained profoundly by winter temperature and early-spring precipitation. Comparisons were also made with local tree-ring data of Norway spruce. Interestingly, both the native and non-native species responded positively to precipitation in June and negatively to precipitation in April. Previous studies have shown that the winter temperature response, demonstrated here for Sitka spruce, is found as Norway spruce growth responses in eastern Estonia, whereas in western Estonia the growth of the latter species is more clearly connected, similar to our findings, to early-summer precipitation. These findings indicate that while the both spruce species remain sensitive to spring/summer moisture regime, the growth of Sitka spruce may actually be less tolerate to winter temperatures, as evident here in western Estonia where the winters may likely be milder than in eastern Estonia. Common to Sitka spruce results from Hiiumaa, tree-ring data representing conspecific native populations from north-west North American sites indicated positive responses to mid-winter temperatures. Based on these results, low winter temperatures and early-summer droughts may both threaten the survival of the remnant individuals of this species in Hiiumaa.

Evolution of Winter Temperature in Toronto, Ontario, Canada: A Case Study of Winters 2013/14 and 2014/15

2017 ◽  
Vol 30 (14) ◽  
pp. 5361-5376 ◽  
Author(s):  
Conor I. Anderson ◽  
William A. Gough
Keyword(s):  
Kendall Test ◽  
Warming Trend ◽  
Winter Temperature ◽  
Eastern Canada ◽  
Record Keeping ◽  
Winter Temperatures ◽  
Cold Events ◽  
Slope Estimation ◽  
Urban Heat

Globally, 2014 and 2015 were the two warmest years on record. At odds with these global records, eastern Canada experienced pronounced annual cold anomalies in both 2014 and 2015, especially during the 2013/14 and 2014/15 winters. This study sought to contextualize these cold winters within a larger climate context in Toronto, Ontario, Canada. Toronto winter temperatures (maximum Tmax, minimum Tmin, and mean Tmean) for the 2013/14 and 2014/15 seasons were ranked among all winters for three periods: 1840/41–2015 (175 winters), 1955/56–2015 (60 winters), and 1985/86–2015 (30 winters), and the average warming trend for each temperature metric during these three periods was analyzed using the Mann–Kendall test and Thiel–Sen slope estimation. The winters of 2013/14 and 2014/15 were the 34th and 36th coldest winters in Toronto since record-keeping began in 1840; however these events are much rarer, relatively, over shorter periods of history. Overall, Toronto winter temperatures have warmed considerably since winter 1840/41. The Mann–Kendall analysis showed statistically significant monotonic trends in winter Tmax, Tmin, and Tmean over the last 175 and 60 years. These trends notwithstanding, there has been no clear signal in Toronto winter temperature since 1985/86. However, there was a statistically significant increase in the diurnal temperature range in that period, indicating an expansion of winter extremes. It is proposed that the possible saturation of urban heat island–related warming in Toronto may partially explain this increase in variation. Also, anomalies in the position of the polar jet stream over Toronto during these cold events are identified. No direct influence of major teleconnections on Toronto winter temperature is found.

scholarly journals Effects of winter conditions on Olympia oyster reproduction and larval yield

2020 ◽  
Author(s):  
Laura H Spencer ◽  
Erin Horkan ◽  
Ryan Crim ◽  
Steven B Roberts
Keyword(s):  
Elevated Temperature ◽  
Winter Temperature ◽  
List Type ◽  
Ostrea Lurida ◽  
Algal Density ◽  
Larval Size ◽  
Olympia Oyster ◽  
Winter Temperatures ◽  
Feeding Regimes ◽  
Larval Production

AbstractFor marine invertebrates that live in temperate regions, reproductive processes are tightly linked to seasonal temperature changes, yet we know little about how reproduction will shift as winters become milder. This study examined effects of winter temperature on spring reproduction in the Olympia oyster, Ostrea lurida. Adults were exposed to two winter temperatures (7°C, 10°C) in the presence of two feeding regimes, high (50k cells/mL) and low (5k cells/mL) algal density, for either 7 weeks or 12 weeks. Following treatments, adults were induced to spawn in common conditions using hatchery techniques, and larvae were reared through settlement to assess viability. Adults overwintered in elevated temperature contained larger oocytes, and those also held in elevated algal density contained more developed sperm. Elevated temperature (10°C) under both feeding regimes resulted in larvae that tended to be larger upon release from the maternal brood chamber. However, winter temperature did not impact fecundity, larval release timing, or larval viability, nor was larval viability related to larval size upon release. In the wild, more developed gametes and larger larvae following milder winters could greatly impact recruitment patterns. When larvae are reared in the hatchery, however, elevated winter temperature will not likely impact larval viability or yield. Interestingly, overwintering duration greatly impacted broodstock survival and larval production. Regardless of winter temperature or feeding rate, broodstock overwintered in the hatchery for 12 weeks produced fewer larvae and had higher mortality during spawning compared to those held for only 7 weeks. Furthermore, broodstock overwintered in the low temperature treatment (7°C) with high algal density (50k cells/mL) experienced high mortality during spawning. Broodstock mortality is disadvantageous for hatcheries, can hinder larval production, and decrease genetic diversity of offspring. We therefore recommend that hatcheries overwinter O. lurida broodstock in slightly warmer temperatures and minimize the amount of time they are held in captivity prior to spawning. Finally, because algal density during winter treatments did not impact broodstock survival or spring larval production, hatcheries may restrict feeding without impacting production, given broodstock are in good condition upon collection.Highlights of the manuscriptMilder winters may result in more developed O. lurida sperm, larger oocytes, and larger larvae, but will not likely impact larval production timing or magnitude, indicating that O. lurida reproduction is relatively resilient to shifting winter temperatures.In a hatchery setting, O. lurida larval size upon release does not predict larval survival, and hatcheries should not presume that smaller O. lurida larvae are of poor quality.When overwintering Ostrea lurida broodstock in the hatchery prior to spring production, chilling seawater to historic winter temperatures is not necessary, nor is feeding broodstock high algal densities, and the amount of time broostock are held prior to spawning should be minimized.

scholarly journals Winter temperature predicts prolonged diapause in pine processionary moth across its geographic range

2018 ◽  
Author(s):  
Md H.R. Salman ◽  
Carmelo P. Bonsignore ◽  
My Ahmed El Alaoui El Fels ◽  
Folco Giomi ◽  
José A. Hodar ◽  
...  
Keyword(s):  
Geographic Range ◽  
Winter Temperature ◽  
Thaumetopoea Pityocampa ◽  
Mortality Factors ◽  
Pine Processionary Moth ◽  
Winter Temperatures ◽  
Important Pest ◽  
Risk Spreading ◽  
Prolonged Diapause ◽  
Diapause Incidence

Prolonged diapause occurs in a number of insects and is interpreted as a way to evade adverse conditions. The winter pine processionary moths (Thaumetopoea pityocampa and Th. wilkinsoni) are important pest of pines and cedars in the Mediterranean region. They are typically univoltine, with larvae feeding across the winter, pupating in spring in the soil and emerging as adults in summer. Pupae may, however, enter a prolonged diapause with adults emerging one or more years later. We tested the effect of spatial variation in winter temperature on the incidence of prolonged diapause, using a total of 64 individual datasets related to insect cohorts over the period 1964-2015 for 36 sites in 7 countries, covering most of the geographic range of the species. We found high variation in prolonged diapause incidence over the species’ range. Insect cohorts exposed to average winter temperatures lower than 0°C were associated with higher prolonged diapause incidence than cohorts exposed to intermediate temperatures. Prolonged diapause may represent a risk-spreading strategy although it is associated with high mortality because of a longer exposure to mortality factors, desiccation, and energy depletion. Climate change, and in particular the increase of winter temperature, may reduce the incidence of prolonged diapause at the colder sites whereas it may increase it at the warmer ones, with consequences on the population dynamics.

scholarly journals Changes in Temperature Seasonality in China: Human Influences and Internal Variability

2019 ◽  
Vol 32 (19) ◽  
pp. 6237-6249 ◽  
Author(s):  
Cheng Qian ◽  
Xuebin Zhang
Keyword(s):  
Internal Variability ◽  
Summer Temperature ◽  
Winter Temperature ◽  
Spatiotemporal Pattern ◽  
Detection And Attribution ◽  
External Forcings ◽  
Observational Uncertainty ◽  
Winter Temperatures ◽  
Warming Hiatus ◽  
Temperature Seasonality

Abstract Temperature seasonality, the difference between summer and winter temperatures in mid–high latitudes, is an important component of the climate. Whether humans have had detectable influences on changing surface temperature seasonality at scales smaller than the subcontinental scale, where humans are directly impacted, is not clear. In this study, the first detection and attribution analysis of changes in temperature seasonality in China has been carried out. Detection and attribution of both summer and winter temperatures were also conducted, with careful consideration of observational uncertainty and the inconsistency between observation and model simulations induced by the long coastline and country border in China. The results show that the response to external forcings is robustly detectable in the spatiotemporal pattern of weakening seasonality and in that of warming winter temperature, although models may have underestimated the observed changes. The response to external forcings is detectable and consistent with the observed change in summer temperature averaged over China. Human influences are detectable in changes in seasonality and summer and winter temperatures, most robustly in winter, and these influences can be separated from those of natural forcing when averaged over China. The recent increase in summer temperature was found to be due to external forcings, and the warming hiatus in winter temperature from 1998 to 2013 was due to a statistically significant cooling trend induced by internal variability. These results will give insights into the understanding of the warming hiatus in China, as well as the hot summers and cold winters in recent years.

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