scholarly journals Biases in the calculation of Southern Hemisphere mean baroclinic eddy growth rate

2009 ◽  
Vol 36 (1) ◽  
Author(s):  
Ian Simmonds ◽  
Eun-Pa Lim
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere

scholarly journals Twentieth Century Winter Changes in Southern Hemisphere Synoptic Weather Modes

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Jorgen S. Frederiksen ◽  
Carsten S. Frederiksen
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere ◽  
Western Australia ◽  
Three Dimensional ◽  
Storm Track ◽  
Intraseasonal Oscillation ◽  
Low Frequency ◽  
Winter Rainfall ◽  
Cloud Band ◽  
Eastern Australia

During the last sixty years, there have been large changes in the southern hemisphere winter circulation and reductions in rainfall particularly in the southern Australian region. Here we examine the corresponding changes in dynamical modes of variability ranging from storm tracks, onset-of-blocking modes, northwest cloud-band disturbances, Antarctic low-frequency modes, intraseasonal oscillations, and African easterly waves. Our study is performed using a global two-level primitive equation instability-model with reanalyzed observed July three-dimensional basic states for the periods 1949–1968, 1975–1994, and 1997–2006. We relate the reduction in the winter rainfall in the southwest of Western Australia since the mid-1970s and in south-eastern Australia since the mid-1990s to changes in growth rate and structures of leading storm track and blocking modes. We find that cyclogenesis and onset-of-blocking modes growing on the subtropical jet have significantly reduced growth rates in the latter periods. On the other hand there is a significant increase in the growth rate of northwest cloud-band modes and intraseasonal oscillation disturbances that cross Australia and are shown to be related to recent positive trends in winter rainfall over northwest Western Australia and central Australia, in general. The implications of our findings are discussed.

scholarly journals Early detection of seasonality and second-wave prediction in the COVID-19 pandemic

2020 ◽  
Author(s):  
Márcio Watanabe
Keyword(s):  
Growth Rate ◽  
Time Series ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Time Series Data ◽  
Seasonal Effects ◽  
Series Data ◽  
Seasonal Effect ◽  
Social Distancing ◽  
The Mean

AbstractSeasonality plays an essential role in the dynamics of many infectious diseases. Its confirmation in an emerging infectious disease is usually done using time series data from several years. By using statistical regression methods for time-series data pooled from more than 50 countries from both hemispheres, we show how to determine its presence in a pandemic at the onset of the seasonal period. We measure its expected effect in the mean transmission rate of SARS-coV-2 and predict when further epidemic outbreaks of COVID-19 will occur. The obtained result in the Northern Hemisphere shows that seasonality reduced the mean growth rate in 222.5% in April 2020. A relative reduction greater than 100% should be interpreted as a reduction changing an increasing rate to a decreasing one. In contrast, at the same moment, the seasonal effect in the Southern Hemisphere increased the mean growth rate in 740.3%. Our analysis simultaneously considers other confounding factors to properly separate them from seasonal effects and, in addition, we measure the mean global effect of social-distancing interventions and its relation with income. Future COVID-19 waves are expected to occur in autumn/winter seasons, typically between September and March in the Northern Hemisphere, and between April and September in the Southern Hemisphere. Simulations of a seasonal SEIR model with a social distancing effect are shown to describe the behavior of COVID-19 outbreaks in several countries. These results provide vital information for policy makers to plan their actions against the new coronavirus disease, particularly in the optimization of social-distancing interventions and vaccination schedules. Ultimately, our methods can be used to identify and measure seasonal effects in a future pandemic.

scholarly journals Growth rates of stratospheric HCFC-22

2007 ◽  
Vol 7 (4) ◽  
pp. 10515-10541
Author(s):  
D. P. Moore ◽  
J. J. Remedios
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere ◽  
Atmospheric Chemistry ◽  
Growth Rates ◽  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
Data Set ◽  
Atmospheric Sounding ◽  
Global Data ◽  
Made In

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E) offers the opportunity to detect and spectrally resolve many atmospheric minor constituents affecting atmospheric chemistry. In this paper, we describe an algorithm produced to retrieve HCFC–22 profiles from MIPAS-E measurements made in 2003 and present results from this scheme between 300 and 50 mb. By comparison with ATMOS (AT–3) version 3 data, we find a mean Northern Hemisphere mid-latitude (20–50° N) HCFC–22 growth rate between 1994 and 2003 of 5.4±0.7 pptv/yr in the lower stratosphere (LS) and a mean LS Southern Hemisphere growth rate (60–80°S) of 6.0±0.7 pptv/yr in the same period. We test the feasibility of using a global data set to estimate the chemical lifetime of HCFC–22 in the LS and we derive this for two regions; 20–50° N (259±38 years) and 60–80° S (288±34 years). From these data we note a global LS lifetime of 274±25 years, significantly longer than previous estimates.

scholarly journals Growth rates of stratospheric HCFC-22

2008 ◽  
Vol 8 (1) ◽  
pp. 73-82 ◽  
Author(s):  
D. P. Moore ◽  
J. J. Remedios
Keyword(s):  
Growth Rate ◽  
Southern Hemisphere ◽  
Atmospheric Chemistry ◽  
Growth Rates ◽  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
Data Set ◽  
Atmospheric Sounding ◽  
Global Data ◽  
Made In

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E) offers the opportunity to detect and spectrally resolve many atmospheric minor constituents affecting atmospheric chemistry. In this paper, we describe an algorithm produced to retrieve HCFC–22 profiles from MIPAS-E measurements made in 2003 and present results from this scheme between 300 and 50 mb. By comparison with ATMOS (AT–3) version 3 data, we find a mean Northern Hemisphere mid-latitude (20–50° N) HCFC–22 growth rate between 1994 and 2003 of 5.4±0.7 pptv/yr in the lower stratosphere (LS) and a mean LS Southern Hemisphere growth rate (60–80° S) of 6.0±0.7 pptv/yr in the same period. We test the feasibility of using a global data set to estimate the chemical lifetime of HCFC–22 in the LS and we derive this for two regions: 20–50° N (246±38 years) and 60–80° S (274±34 years). From these data we note a global LS lifetime of 260±25 years, significantly longer than previous estimates.

scholarly journals The Greater Proportion of Born-Light Progeny from Sows Mated in Summer Contributes to Increased Carcass Fatness Observed in Spring

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2080
Author(s):  
Fan Liu ◽  
Erin M. Ford ◽  
Rebecca S. Morrison ◽  
Chris J. Brewster ◽  
David J. Henman ◽  
...  
Keyword(s):  
Growth Rate ◽  
Seasonal Variation ◽  
Birth Weight ◽  
Southern Hemisphere ◽  
Rectal Temperature ◽  
Feed Intake ◽  
Live Weight ◽  
Mating Season ◽  
Early Gestation ◽  
Pig Carcasses

The backfat of pig carcasses is greater in spring than summer in Australia. The unexplained seasonal variation in carcass backfat creates complications for pig producers in supplying consistent lean carcasses. As a novel explanation, we hypothesised that the increased carcass fatness in spring was due to a greater percentage of born-light progeny from sows that were mated in summer and experienced hot conditions during early gestation. The first part of our experiment compared the birth weight of piglets born to the sows mated in summer (February, the Southern Hemisphere) with those born to sows mated in autumn (May; the Southern Hemisphere), and the second part of the experiment compared the growth performance and carcass fatness of the progeny that were stratified as born-light (0.7–1.1 kg) and born-normal (1.3–1.7 kg) from the sows mated in these two seasons. The results showed that the sows mated in summer experienced hotter conditions during early gestation as evidenced by an increased respiration rate and rectal temperature, compared with those mated in autumn. The sows mated in summer had a greater proportion of piglets that were born ≤1.1 kg (24.2% vs. 15.8%, p < 0.001), lower average piglet birth weight (1.39 kg vs. 1.52 kg, p < 0.001), lower total litter weights (18.9 kg vs. 19.5 kg, p = 0.044) and lower average placental weight (0.26 vs. 0.31 kg, p = 0.011) than those mated in autumn, although litter sizes were similar. Feed intake and growth rate of progeny from 14 weeks of age to slaughter (101 kg live weight) were greater for the born-normal than born-light pigs within the progeny from sows mated in autumn, but there was no difference between the born-light and normal progeny from sows mated in summer, as evidenced by the interaction between piglet birth weight and sow mating season (Both p < 0.05). Only the born-light piglets from the sows mated in summer had a greater backfat thickness and loin fat% than the progeny from the sows mated in autumn, as evidenced by a trend of interaction between piglet birth weight and sow mating season (Both p < 0.10). In conclusion, the increased proportion of born-light piglets (0.7–1.1 kg range) from the sows mated in summer contributed to the increased carcass fatness observed in spring.

scholarly journals Abrupt seasonal transitions in land carbon uptake in 2015

2017 ◽  
Author(s):  
Chao Yue ◽  
Philippe Ciais ◽  
Ana Bastos ◽  
Frederic Chevallier ◽  
Yi Yin ◽  
...  
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Southern Hemisphere ◽  
Carbon Sink ◽  
Growing Season ◽  
Satellite Observations ◽  
Carbon Uptake ◽  
Co2 Fluxes ◽  
Abrupt Transition ◽  
The Tropics

Abstract. The year 2015 saw a record atmospheric CO2 growth rate associated with a weaker than usual land carbon sink. Paradoxically, it was also the greenest year since 2000 according to satellite observations of vegetation greenness. To reconcile these two seemingly paradoxical observations, we examined the patterns of CO2 fluxes using two atmospheric inversions. Inversion results indicate that the year 2015 had a higher than usual northern land carbon uptake in spring and summer, consistent with the greening anomaly. This higher uptake was however followed by a larger source of CO2 in autumn, suggesting a coupling between growing season uptake and late season release of CO2. For the tropics and Southern Hemisphere, a strong and abrupt transition toward a large carbon source for the last trimester of 2015 is discovered, concomitant with the El Niño development. This abrupt transition of terrestrial tropical CO2 fluxes between two consecutive seasons is the largest ever found in the inversion records.

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