scholarly journals The JCMT Transient Survey: Stochastic and Secular Variability of Protostars and Disks In the Submillimeter Region Observed over 18 Months

2018 ◽  
Vol 854 (1) ◽  
pp. 31 ◽  
Author(s):  
Doug Johnstone ◽  
Gregory J. Herczeg ◽  
Steve Mairs ◽  
Jennifer Hatchell ◽  
Geoffrey C. Bower ◽  
...  
Keyword(s):  
Secular Variability

An Assessment of ENSO-Scale Secular Variability

1995 ◽  
Vol 8 (6) ◽  
pp. 1584-1599 ◽  
Author(s):  
X. L. Wang ◽  
C. F. Ropelewski
Keyword(s):  
Secular Variability

scholarly journals Tales of the Venerable Honolulu Tide Gauge*

2006 ◽  
Vol 36 (6) ◽  
pp. 967-996 ◽  
Author(s):  
John A. Colosi ◽  
Walter Munk
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Internal Tide ◽  
Variable Density ◽  
Internal Tides ◽  
Density Structure ◽  
Mean Sea Level ◽  
Proposed Model ◽  
Secular Variability ◽  
Internal Component

Abstract Surface expressions of internal tides constitute a significant component of the total recorded tide. The internal component is strongly modulated by the time-variable density structure, and the resulting perturbation of the recorded tide gives a welcome look at twentieth-century interannual and secular variability. Time series of mean sea level hSL(t) and total recorded M2 vector aTT(t) are extracted from the Honolulu 1905–2000 and Hilo 1947–2000 (Hawaii) tide records. Internal tide parameters are derived from the intertidal continuum surrounding the M2 frequency line and from a Cartesian display of aTT(t), yielding aST = 16.6 and 22.1 cm, aIT = 1.8 and 1.0 cm for surface and internal tides at Honolulu and Hilo, respectively. The proposed model aTT(t) = aST + aIT cosθIT(t) is of a phase-modulated internal tide generated by the surface tide at some remote point and traveling to the tide gauge with velocity modulated by the underlying variable density structure. Mean sea level hSL(t) [a surrogate for the density structure and hence for θIT(t)] is coherent with aIT(t) within the decadal band 0.2–0.5 cycles per year. For both the decadal band and the century drift the recorded M2 amplitude is high when sea level is high, according to δaTT = O(0.1δhSL). The authors attribute the recorded secular increase in the Honolulu M2 amplitude from aTT = 16.1 to 16.9 cm between 1915 and 2000 to a 28° rotation of the internal tide vector in response to ocean warming.

Secular variability of the geocoronal Balmer-alpha brightness: magnetic activity and possible human influences

2001 ◽  
Vol 106 (A12) ◽  
pp. 28819-28830 ◽  
Author(s):  
R. B. Kerr ◽  
R. Garcia ◽  
X. He ◽  
J. Noto ◽  
R. S. Lancaster ◽  
...  
Keyword(s):  
Magnetic Activity ◽  
Secular Variability

scholarly journals Indicators of Antarctic ozone depletion: 1979 to 2019

2020 ◽  
Author(s):  
Greg E. Bodeker ◽  
Stefanie Kremser
Keyword(s):  
Ozone Depletion ◽  
Learning Algorithm ◽  
Total Column Ozone ◽  
Secular Variability ◽  
Antarctic Ozone ◽  
Time Changes ◽  
Ozone Depleting Substances ◽  
Winter Time ◽  
Column Ozone ◽  
The Antarctic

Abstract. The National Institute of Water and Atmospheric Research/Bodeker Scientific (NIWA-BS) total column ozone (TCO) database, and the associated BS-filled TCO database, have been updated to cover the period 1979 to 2019, bringing both to version 3.5.1 (V3.5.1). The BS-filled database builds on the NIWA-BS database by using a machine-learning algorithm to fill spatial and temporal data gaps to provide gap-free TCO fields over Antarctic. These filled TCO fields then provide a more complete picture of winter-time changes in the ozone layer over Antarctica. The BS-filled database has been used to calculate continuous, homogeneous time series of indicators of Antarctic ozone depletion from 1979 to 2019, including (i) daily values of the ozone mass deficit based on TCO below a 220 DU threshold, (ii) daily measures of the area over Antarctica where TCO levels are below 150 DU, below 220 DU, more than 30 % below 1979 to 1981 climatological means, and more than 50 % below 1979 to 1981 climatological means, (iii) the date of disappearance of 150 DU TCO values, 220 DU TCO values, values 30 % or more below 1979 to 1981 climatological means, and values 50 % or more below 1979 to 1981 climatological means, for each year, and (iv) daily minimum TCO values over the range 75° S to 90° S equivalent latitude. Since both the NIWA-BS and BS-filled databases provide uncertainties on every TCO value, the Antarctic ozone depletion metrics are provided, for the first time, with fully traceable uncertainties. To gain insight into how the vertical distribution of ozone over Antarctica has changed over the past 36 years, ozone concentrations, combined and homogenized from several satellite-based ozone monitoring instruments as well as the global ozonesonde network, were also analysed. A robust attribution to changes in the drivers of long-term secular variability in these metrics has not been performed in this analysis. As a result, statements about the recovery of Antarctic TCO from the effects of ozone depleting substances cannot be made. That said, there are clear indications of a change in trend in many of the metrics reported on here around the turn of the century, close to when Antarctic stratospheric concentrations of chlorine and bromine peaked.

scholarly journals Solar total and spectral irradiance reconstruction over the last 9000 years

2018 ◽  
Vol 620 ◽  
pp. A120 ◽  
Author(s):  
C.-J. Wu ◽  
N. A. Krivova ◽  
S. K. Solanki ◽  
I. G. Usoskin
Keyword(s):  
Sunspot Number ◽  
Maunder Minimum ◽  
Spectral Irradiance ◽  
Cosmogenic Isotopes ◽  
Secular Variability ◽  
Isotope Record ◽  
Long Term Trends ◽  
A Chain ◽  
The Individual ◽  
Solar Influence

Context.Changes in solar irradiance and in its spectral distribution are among the main natural drivers of the climate on Earth. However, irradiance measurements are only available for less than four decades, while assessment of solar influence on Earth requires much longer records.Aims.The aim of this work is to provide the most up-to-date physics-based reconstruction of the solar total and spectral irradiance (TSI/SSI) over the last nine millennia.Methods.The concentrations of the cosmogenic isotopes14C and10Be in natural archives have been converted to decadally averaged sunspot numbers through a chain of physics-based models. TSI and SSI are reconstructed with an updated SATIRE model. Reconstructions are carried out for each isotope record separately, as well as for their composite.Results.We present the first ever SSI reconstruction over the last 9000 years from the individual14C and10Be records as well as from their newest composite. The reconstruction employs physics-based models to describe the involved processes at each step of the procedure.Conclusions.Irradiance reconstructions based on two different cosmogenic isotope records, those of14C and10Be, agree well with each other in their long-term trends despite their different geochemical paths in the atmosphere of Earth. Over the last 9000 years, the reconstructed secular variability in TSI is of the order of 0.11%, or 1.5 W m−2. After the Maunder minimum, the reconstruction from the cosmogenic isotopes is consistent with that from the direct sunspot number observation. Furthermore, over the nineteenth century, the agreement of irradiance reconstructions using isotope records with the reconstruction from the sunspot number by Chatzistergos et al. (2017, A&A, 602, A69) is better than that with the reconstruction from the WDC-SILSO series (Clette et al. 2014, Space Sci. Rev., 186, 35), with a lowerχ2-value.

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