scholarly journals Study of the Large-Scale Temperature Structure of the Perseus Cluster with Suzaku

2010 ◽  
Vol 62 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Sho Nishino ◽  
Yasushi Fukazawa ◽  
Katsuhiro Hayashi ◽  
Kazuhiro Nakazawa ◽  
Takaaki Tanaka
Keyword(s):  
Large Scale ◽  
Temperature Structure ◽  
Scale Temperature ◽  
Perseus Cluster

scholarly journals On the short-term variability of turbulence and temperature in the winter mesosphere

2018 ◽  
Vol 36 (4) ◽  
pp. 1099-1116
Author(s):  
Gerald A. Lehmacher ◽  
Miguel F. Larsen ◽  
Richard L. Collins ◽  
Aroh Barjatya ◽  
Boris Strelnikov
Keyword(s):  
Attitude Control ◽  
Large Scale ◽  
Lower Thermosphere ◽  
Density Fluctuations ◽  
Large Temperature ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Temperature Structure ◽  
Wind Shears

Abstract. Four mesosphere–lower thermosphere temperature and turbulence profiles were obtained in situ within ∼30 min and over an area of about 100 by 100 km during a sounding rocket experiment conducted on 26 January 2015 at Poker Flat Research Range in Alaska. In this paper we examine the spatial and temporal variability of mesospheric turbulence in relationship to the static stability of the background atmosphere. Using active payload attitude control, neutral density fluctuations, a tracer for turbulence, were observed with very little interference from the payload spin motion, and with high precision (<0.01 %) at sub-meter resolution. The large-scale vertical temperature structure was very consistent between the four soundings. The mesosphere was almost isothermal, which means more stratified, between 60 and 80 km, and again between 88 and 95 km. The stratified regions adjoined quasi-adiabatic regions assumed to be well mixed. Additional evidence of vertical transport and convective activity comes from sodium densities and trimethyl aluminum trail development, respectively, which were both observed simultaneously with the in situ measurements. We found considerable kilometer-scale temperature variability with amplitudes of 20 K in the stratified region below 80 km. Several thin turbulent layers were embedded in this region, differing in width and altitude for each profile. Energy dissipation rates varied between 0.1 and 10 mW kg−1, which is typical for the winter mesosphere. Very little turbulence was observed above 82 km, consistent with very weak small-scale gravity wave activity in the upper mesosphere during the launch night. On the other hand, above the cold and prominent mesopause at 102 km, large temperature excursions of +40 to +70 K were observed. Simultaneous wind measurements revealed extreme wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0<Ri<0.25) were detected in the lower thermosphere. The experiment was launched into a bright auroral arc under moderately disturbed conditions (Kp∼5).

scholarly journals OMICS in Ecology: Systems Level Analyses ofHalobacterium salinarumReveal Large-scale Temperature-Mediated Changes and a Requirement of CctA for Thermotolerance

2014 ◽  
Vol 18 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Rueyhung Roc Weng ◽  
Hung-Wei Shu ◽  
See-Wen Chin ◽  
Yuchieh Kao ◽  
Ting-Wen Chen ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Temperature

Design and Implementation of Large-Scale Temperature Stability Control System

2014 ◽  
Vol 644-650 ◽  
pp. 313-316
Author(s):  
Wen Lai Liu
Keyword(s):  
Control System ◽  
System Design ◽  
Large Scale ◽  
Control Method ◽  
Temperature Stability ◽  
Stability Control ◽  
Control System Design ◽  
Scale Temperature ◽  
Stability Control System ◽  
The Stability

large-scale temperature stability control method is studied in this paper. In the process of large-scale temperature control, the stability of control is a very important indicator. To this end, this paper proposes a large-scale temperature stability control algorithm based on hierarchical control method. Balance equation of large-scale temperature stability control is created for the effective transmission of control data. According to the constant control theory, large-scale temperature stability control system design is achieved. Experimental results show that the proposed algorithm for large-scale temperature stability control system design, can greatly improve the stability of control, and get the satisfactory results.

Responses of Shallow Cumulus Convection to Large-Scale Temperature and Moisture Perturbations: A Comparison of Large-Eddy Simulations and a Convective Parameterization Based on Stochastically Entraining Parcels

2012 ◽  
Vol 69 (6) ◽  
pp. 1936-1956 ◽  
Author(s):  
Ji Nie ◽  
Zhiming Kuang
Keyword(s):  
Large Scale ◽  
Potential Temperature ◽  
Large Eddy Simulations ◽  
Cumulus Parameterization ◽  
Temperature Perturbation ◽  
Cumulus Convection ◽  
Positive Temperature ◽  
Shallow Cumulus ◽  
Scale Temperature ◽  
Large Eddy

Abstract Responses of shallow cumuli to large-scale temperature/moisture perturbations are examined through diagnostics of large-eddy simulations (LESs) of the undisturbed Barbados Oceanographic and Meteorological Experiment (BOMEX) case and a stochastic parcel model. The perturbations are added instantaneously and allowed to evolve freely afterward. The parcel model reproduces most of the changes in the LES-simulated cloudy updraft statistics in response to the perturbations. Analyses of parcel histories show that a positive temperature perturbation forms a buoyancy barrier, which preferentially eliminates parcels that start with lower equivalent potential temperature or have experienced heavy entrainment. Besides the amount of entrainment, the height at which parcels entrain is also important in determining their fate. Parcels entraining at higher altitudes are more likely to overcome the buoyancy barrier than those entraining at lower altitudes. Stochastic entrainment is key for the parcel model to reproduce the LES results. Responses to environmental moisture perturbations are quite small compared to those to temperature perturbations because changing environmental moisture is ineffective in modifying buoyancy in the BOMEX shallow cumulus case. The second part of the paper further explores the feasibility of a stochastic parcel–based cumulus parameterization. Air parcels are released from the surface layer and temperature/moisture fluxes effected by the parcels are used to calculate heating/moistening tendencies due to both cumulus convection and boundary layer turbulence. Initial results show that this conceptually simple parameterization produces realistic convective tendencies and also reproduces the LES-simulated mean and variance of cloudy updraft properties, as well as the response of convection to temperature/moisture perturbations.

scholarly journals Comments on “Reconstruction of the Extratropical NH Mean Temperature over the Last Millennium with a Method That Preserves Low-Frequency Variability”

2012 ◽  
Vol 25 (22) ◽  
pp. 7991-7997 ◽  
Author(s):  
Anders Moberg
Keyword(s):  
Large Scale ◽  
Low Frequency ◽  
Temperature Reconstruction ◽  
Noise Variance ◽  
Low Frequencies ◽  
Scale Temperature ◽  
Low Frequency Variability ◽  
High Frequency Variability ◽  
Frequency Temperature ◽  
Correct Estimate

Abstract Christiansen and Ljungqvist have presented an extratropical NH temperature reconstruction using a method (LOC) that they claim “preserves” low-frequency variability, at the expense of exaggerated high-frequency variability. Using theoretical arguments and a pseudoproxy experiment, it is demonstrated here that the LOC method is not guaranteed to preserve variability at any frequency. Rather, LOC reconstructions will have more variance than true large-scale temperature averages at all frequencies. This variance inflation, however, can be negligible at those frequencies where the noise variance in individual proxies is small enough to be effectively cancelled when computing an average over the available proxies. Because the proxy noise variance at low frequencies cannot be directly estimated, and thus has to be regarded as unknown, it is safer to regard a reconstruction with the LOC method as providing an estimate of the upper bound of the large-scale low-frequency temperature variability rather than one with a correct estimate of this variance.

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