scholarly journals Comparing temperature of subauroral mesopause over Yakutia with SABER radiometer data for 2002–2014

2017 ◽  
Vol 3 (2) ◽  
pp. 58-63
Author(s):  
Анастасия Аммосова ◽  
Anastasiya Ammosova ◽  
Галина Гаврильева ◽  
Galina Gavrilyeva ◽  
Петр Аммосов ◽  
...  
Keyword(s):  
Spectral Measurements ◽  
Satellite Measurements ◽  
Mesopause Region ◽  
Temperature Variations ◽  
Broadband Emission ◽  
Long Term Trends ◽  
The Difference ◽  
Temperature Time ◽  
Good Agreement

We present the temperature database for the mesopause region, which was collected from spectral measurements of bands O2(0-1) and OH(6-2) with the infrared spectrograph SP-50 at the Maimaga station (63° N; 129.5° E) in 2002–2014. The temperature time series covers 11-year solar cycle. It is compared with the temperature obtained with the Sounding of the At-mosphere using Broadband Emission Radiometry in-strument (SABER, v.1.07 and v.2.0), installed onboard the TIMED satellite. We compare temperatures meas-ured during satellite passes at distances under 500 km from the intersection of the spectrograph sighting line with the hydroxyl emitting layer (~87 km) and oxygen emitting layer (~95 km). The time criterion is 30 min. We observe that there is a seasonal dependence of the difference between the ground-based and satellite measurements. The data obtained using SABER v2.0 show good agreement with the temperatures measured with the infrared digital spectrograph. The analysis we carried out allows us to conclude that a series of rotational temperatures obtained at the Maimaga station can be used to study temperature variations on different time scales including long-term trends at the mesopause height

scholarly journals Comparing temperature of subauroral mesopause over Yakutia with SABER radiometer data for 2002–2014

2017 ◽  
Vol 3 (2) ◽  
pp. 54-59
Author(s):  
Анастасия Аммосова ◽  
Anastasiya Ammosova ◽  
Галина Гаврильева ◽  
Galina Gavrilyeva ◽  
Петр Аммосов ◽  
...  
Keyword(s):  
Spectral Measurements ◽  
Satellite Measurements ◽  
Mesopause Region ◽  
Temperature Variations ◽  
Broadband Emission ◽  
Long Term Trends ◽  
The Difference ◽  
Temperature Time ◽  
Good Agreement

We present the temperature database for the mesopause region, which was collected from spectral measurements of bands O2(0-1) and OH(6-2) with the infrared spectrograph SP-50 at the Maimaga station (63° N; 129.5° E) in 2002–2014. The temperature time series covers 11-year solar cycle. It is compared with the temperature obtained with the Sounding of the At-mosphere using Broadband Emission Radiometry in-strument (SABER, v.1.07 and v.2.0), installed onboard the TIMED satellite. We compare temperatures meas-ured during satellite passes at distances under 500 km from the intersection of the spectrograph sighting line with the hydroxyl emitting layer (~87 km) and oxygen emitting layer (~95 km). The time criterion is 30 min. We observe that there is a seasonal dependence of the difference between the ground-based and satellite measurements. The data obtained using SABER v2.0 show good agreement with the temperatures measured with the infrared digital spectrograph. The analysis we carried out allows us to conclude that a series of rotational temperatures obtained at the Maimaga station can be used to study temperature variations on different time scales including long-term trends at the mesopause height

scholarly journals Comparison of VLT/X-shooter OH and O<sub>2</sub> rotational temperatures with consideration of TIMED/SABER emission and temperature profiles

2016 ◽  
Vol 16 (8) ◽  
pp. 5021-5042 ◽  
Author(s):  
Stefan Noll ◽  
Wolfgang Kausch ◽  
Stefan Kimeswenger ◽  
Stefanie Unterguggenberger ◽  
Amy M. Jones
Keyword(s):  
Local Thermodynamic Equilibrium ◽  
Rotational Level ◽  
Profile Data ◽  
Selected Lines ◽  
Mesopause Region ◽  
Very Large Telescope ◽  
High Emission ◽  
Long Term Trends ◽  
Good Agreement

Abstract. Rotational temperatures Trot derived from lines of the same OH band are an important method to study the dynamics and long-term trends in the mesopause region near 87 km. To measure realistic temperatures, the rotational level populations have to be in local thermodynamic equilibrium (LTE). However, this might not be fulfilled, especially at high emission altitudes. In order to quantify possible non-LTE contributions to the OH Trot as a function of the upper vibrational level v′, we studied a sample of 343 echelle spectra taken with the X-shooter spectrograph at the Very Large Telescope at Cerro Paranal in Chile. These data allowed us to analyse 25 OH bands in each spectrum. Moreover, we could measure lines of O2b(0-1), which peaks at about 94 to 95 km, and O2a(0-0) with an emission peak at about 90 km. The latter altitude is reached in the second half of the night after a rise of several km because of the decay of a daytime population of excited O2. Since the radiative lifetimes for the upper levels of the two O2 bands are relatively long, the derived Trot are not significantly affected by non-LTE contributions. These bands are well suited for a comparison with OH if the differences in the emission profiles are corrected. For different sample averages, we made these corrections by using OH emission, O2a(0-0) emission, and CO2-based temperature profile data from the multi-channel radiometer SABER on the TIMED satellite. The procedure relies on differences of profile-weighted SABER temperatures. For an O2a(0-0)-based reference profile at 90 km, we found a good agreement of the O2 with the SABER-related temperatures, whereas the OH temperatures, especially for the high and even v′, showed significant excesses with a maximum of more than 10 K for v′ = 8. The exact value depends on the selected lines and molecular parameters. We could also find a nocturnal trend towards higher non-LTE effects, particularly for high v′. The amplitude of these variations can be about 2 K or less, which tends to be significantly smaller than the total amount of the non-LTE contributions. The variations revealed may be important for dynamical studies based on Trot derived from OH bands with high v′.

scholarly journals Long-term trends observed in the middle atmosphere temperatures using ground based LIDARs and satellite borne measurements

2014 ◽  
Vol 32 (3) ◽  
pp. 301-317 ◽  
Author(s):  
P. Kishore ◽  
M. Venkat Ratnam ◽  
I. Velicogna ◽  
V. Sivakumar ◽  
H. Bencherif ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Southern Oscillation ◽  
Warming Trend ◽  
Satellite Measurements ◽  
Long Term Trends ◽  
Maximum Warming ◽  
Cooling Trend ◽  
Term Data ◽  
Good Agreement

Abstract. Long-term data available from Lidar systems located at three different locations namely São José dos Campos, Brazil (23.2° S, 45.8° W), Gadanki (13.5° N, 79.2° E) and Reunion (20.8° S, 55.5° E) have been used to investigate the long-term variations like Annual, Semi-annual, Quasi-biennial, El Nino Southern Oscillation and solar cycle. These oscillations are also extracted from simultaneous satellite borne measurements of HALogen Occultation Experiment (HALOE) instrument onboard UARS and SABER onboard TIMED over these stations making largest time series covering the entire middle atmosphere. A good agreement is found between the LIDAR and satellite-derived amplitudes and phases between 30 and 65 km altitude, which suggests that satellite measurements can be used to investigate the long-term trends globally. Latter measurements are extended to 80 km in order to further investigate these oscillations. Large difference in the amplitudes between the eastern pacific and western pacific is noticed in these oscillations. Changing from cooling trends in the stratosphere to warming trends in the mesosphere occurs more or less at altitude around 70 km altitude and this result agrees well with that observed by satellite measurements reported in the literature. The peak in the cooling trend does not occur at a fixed altitude in the stratosphere however maximum warming trend is observed around 75 km at all the stations. The observed long-term trends including various oscillations are compared with that reported with various techniques.

scholarly journals Comparison of VLT/X-shooter OH and O<sub>2</sub> rotational temperatures with consideration of TIMED/SABER emission and temperature profiles

2015 ◽  
Vol 15 (21) ◽  
pp. 30793-30856
Author(s):  
S. Noll ◽  
W. Kausch ◽  
S. Kimeswenger ◽  
S. Unterguggenberger ◽  
A. M. Jones
Keyword(s):  
Local Thermodynamic Equilibrium ◽  
Rotational Level ◽  
Boltzmann Distribution ◽  
Mesopause Region ◽  
Very Large Telescope ◽  
High Emission ◽  
Long Term Trends ◽  
Non Local ◽  
Good Agreement

Abstract. Rotational temperatures Trot derived from lines of the same OH band are an important method to study the dynamics and long-term trends in the mesopause region near 87 km. To measure realistic temperatures, a corresponding Boltzmann distribution of the rotational level populations has to be achieved. However, this might not be fulfilled, especially at high emission altitudes. In order to quantify possible non-local thermodynamic equilibrium (non-LTE) contributions to the OH Trot as a function of the upper vibrational level v', we studied a sample of 343 echelle spectra taken with the X-shooter spectrograph at the Very Large Telescope at Cerro Paranal in Chile. These data allowed us to analyse 25 OH bands in each spectrum. Moreover, we could measure lines of O2b(0-1), which peaks at about 94 to 95 km, and O2a(0-0) with an emission peak at about 90 km. The latter altitude is reached in the second half of the night after a rise of several km because of the decay of a daytime population of excited O2. Since the radiative lifetimes for the upper levels of the two O2 bands are relatively long, the derived Trot are not significantly affected by non-LTE contributions. These bands are well suited for a comparison with OH if the differences in the emission profiles are corrected. For different sample averages, we made these corrections by using OH emission, O2a(0-0) emission, and CO2-based temperature profile data from the multi-channel radiometer SABER on the TIMED satellite. The procedure relies on differences of profile-weighted SABER temperatures. For an O2a(0-0)-based reference profile at 90 km, we found a good agreement of the O2 with the SABER-related temperatures, whereas the OH temperatures, especially for the high and even v', showed significant excesses with a maximum of more than 10 K for v' = 8. The exact value depends on the selected lines and molecular parameters. We could also find a nocturnal trend towards higher non-LTE effects, particularly for high v'. The amplitude of these variations can be about 2 K or less, which tends to be significantly smaller than the total amount of the non-LTE contributions. The found variations can be critical for dynamical studies based on Trot derived from OH bands with high v'.

scholarly journals Determining Long-Term Trends of Four Fast-Eutrophicated Lakes in China and Finland

2015 ◽  
Vol 8 (1) ◽  
pp. 39 ◽  
Author(s):  
Mengna Liao ◽  
Ge Yu ◽  
Anne-Mari Ventelä ◽  
Xuhui Dong
Keyword(s):  
Water Quality ◽  
Anthropogenic Impacts ◽  
Turning Points ◽  
Dynamic Modelling ◽  
Sharp Change ◽  
Temperature Variations ◽  
Long Term Trends ◽  
Nutrient Changes ◽  
Water Quality Trends

<p>Lake eutrophication has increased in pace in recent decades and has caused serious environmental problems However, the development trends have not been fully determined as it is difficult to recognize complex effects emanating from both climate and human mechanisms. China has many lakes in different trophic stages, which represent three developing stages from forest- to agriculture-, and then to urban-lake, typically in Lakes Lugu, Taibai, and Taihu. To determine long-term water quality trends, the three lakes were chosen for statistic analysis on dominant effects on the diatom-inferred nutrient changes, and to undertake dynamic modelling regarding climate-controlled nutrient changes. The results indicate the significant turning points of water quality in Lakes Lugu, Taibai and Taihu occurring in the 1990s, 1950s and 1940s respectively, which were effected from human activities by increases in tourism, farming and urbanization respectively. Water quality changes in Lakes Lugu, Taibai and Taihu captured 68.4%, 54.9%, and 86.0% of the temperature variations before the turning points. The anthropogenic impacts explained 84.0%, 96.4% and 96.0% of the water quality variations after the turning points, where the sharp change of water quality by human activity has played an accelerated effect on the gentle change of temperature. Compared with the 4 phases of water quality development in Pyhäjärvi Lake (SW Finland), Lakes Lugu and Taibai have experienced the 1<sup>st</sup> and 2<sup>nd</sup> phases, and Taihu has experienced from the 2<sup>nd</sup> to 3<sup>rd</sup> phases during the last 150 years. Phase 4 has not occurred in the three lakes, but it is a key period during the eutropication we need to pay attentions.</p>

scholarly journals The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

2008 ◽  
Vol 8 (3) ◽  
pp. 505-522 ◽  
Author(s):  
G. L. Manney ◽  
W. H. Daffer ◽  
K. B. Strawbridge ◽  
K. A. Walker ◽  
C. D. Boone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
High Arctic ◽  
Trace Gas ◽  
Satellite Measurements ◽  
Broadband Emission ◽  
Gas Measurements ◽  
Chemistry Experiment ◽  
Very High ◽  
Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

scholarly journals A review of recent MLT studies at low latitudes

2004 ◽  
Vol 22 (9) ◽  
pp. 3261-3275 ◽  
Author(s):  
B. R. Clemesha
Keyword(s):  
Lower Thermosphere ◽  
Temperature Structure ◽  
Mesopause Region ◽  
The Pacific ◽  
Low Latitudes ◽  
Long Term Trends ◽  
The Caribbean ◽  
Temperature Inversions ◽  
Mlt Region

Abstract. Recent years have shown a continuing interest in studies of the mesosphere-lower thermosphere region at low latitudes, with more than 50 papers dealing specifically with this area published over the past 5 years. Experimental ground-based work has been carried out mainly in South America and the Caribbean, India and the Pacific areas. Subjects of interest include gravity waves, tides and planetary waves, the temperature structure of the mesopause region, with special reference to temperature inversions and the two-level mesopause, sporadic neutral layers and their relationship with ionized layers, the possible effects of the micrometeoroid influx, and long-term trends in the MLT region. Experimental techniques in use include MF, MST and meteor radar, lidar, airglow (including satellite-borne limb-scanning measurements) and rocket-borne instruments. Airglow imaging has shown itself to be a particularly useful technique, mainly for studying gravity wave propagation in the MLT region. This paper will present highlights of recent work and will discuss some of the problems which remain to be resolved.

Long-Term Trends in Prehistoric Fishing and Hunting on Tobago, West Indies

2006 ◽  
Vol 17 (3) ◽  
pp. 316-334 ◽  
Author(s):  
David W. Steadman ◽  
Sharyn Jones
Keyword(s):  
Species Richness ◽  
Relative Abundance ◽  
West Indies ◽  
Sea Turtles ◽  
Food Preferences ◽  
Reef Fishes ◽  
Archaeological Sites ◽  
Long Term Trends ◽  
The Difference

AbstractWe compare the bone assemblages of Milford 1 (TOB-3) and Golden Grove (TOB-13) in Tobago, West Indies. Milford 1 is a small preceramic occupation (ca. 3000-2800 cal B.P.), whereas Golden Grove is a large ceramic-period village (ca. 1700-900 cal B.P.). Species richness at TOB-13 is greater than at TOB-3, both in marine (67 vs. 39 fishes) and terrestrial (32 vs. 9) taxa. Major shifts in marine exploitation from the preceramic to ceramic periods can be seen in relative abundance of tuna, toadfishes, and in fishes inhabiting mangrove and brackish water environments, and decreases in relative abundance of parrotfish, carnivorous reef fishes, and sea turtles. The abundance of tuna bones at TOB-13 is uniquely high among West Indian archaeological sites. For terrestrial taxa, the difference in species richness exceeds the expected, including decreased specialization on big game (peccaries) at TOB-13, with a greater tendency to hunt reptiles, birds, and mammals of all sizes at TOB-3. Factors underlying the shifts in fishing and hunting may include different collection methods and food preferences of non-Arawakan (preceramic) vs. Arawakan (ceramic) peoples, as well as human-induced declines in populations of peccaries, sea turtles, and selected fish species. Another possible factor is site setting, with the inhabitants of TOB-13 having enhanced access to mangrove habitats.

scholarly journals Long-Term EEG Component Analysis Method Based on Lasso Regression

Algorithms ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 271
Author(s):  
Hongjian Bo ◽  
Haifeng Li ◽  
Boying Wu ◽  
Hongwei Li ◽  
Lin Ma
Keyword(s):  
Lasso Regression ◽  
Analysis Method ◽  
Acoustic Features ◽  
Cognitive Studies ◽  
Eeg Data ◽  
The Difference ◽  
The Relationship ◽  
Electroencephalogram Eeg ◽  
Good Agreement

At present, there are very few analysis methods for long-term electroencephalogram (EEG) components. Temporal information is always ignored by most of the existing techniques in cognitive studies. Therefore, a new analysis method based on time-varying characteristics was proposed. First of all, a regression model based on Lasso was proposed to reveal the difference between acoustics and physiology. Then, Permutation Tests and Gaussian fitting were applied to find the highest correlation. A cognitive experiment based on 93 emotional sounds was designed, and the EEG data of 10 volunteers were collected to verify the model. The 48-dimensional acoustic features and 428 EEG components were extracted and analyzed together. Through this method, the relationship between the EEG components and the acoustic features could be measured. Moreover, according to the temporal relations, an optimal offset of acoustic features was found, which could obtain better alignment with EEG features. After the regression analysis, the significant EEG components were found, which were in good agreement with cognitive laws. This provides a new idea for long-term EEG components, which could be applied in other correlative subjects.

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