scholarly journals Determining Longwave Forcing and Feedback Using Infrared Spectra and GNSS Radio Occultation

2010 ◽  
Vol 23 (22) ◽  
pp. 6027-6035 ◽  
Author(s):  
Yi Huang ◽  
Stephen S. Leroy ◽  
James G. Anderson
Keyword(s):  
Water Vapor ◽  
Radiative Forcing ◽  
Radio Occultation ◽  
Optimal Detection ◽  
Tropospheric Temperature ◽  
Data Types ◽  
Mean Values ◽  
Stratospheric Temperature ◽  
Infrared Spectral ◽  
High Level

Abstract The authors investigate whether combining a data type derived from radio occultation (RO) with the infrared spectral data in an optimal detection method improves the quantification of longwave radiative forcing and feedback. Signals derived from a doubled-CO2 experiment in a theoretical study are used. When the uncertainties in both data types are conservatively estimated, jointly detecting the feedbacks of tropospheric temperature and water vapor, stratospheric temperature, and high-level cloud from the two data types should reduce the mean errors by more than 50%. This improvement is achieved because the RO measurement helps disentangle the radiance signals that are ambiguous in the infrared spectrum. The result signifies the complementary information content in infrared spectral and radio occultation data types, which can be effectively combined in optimal detection to accurately quantify the longwave radiative forcing and feedback. The results herein show that the radiative forcing of CO2 and the longwave radiative feedbacks of tropospheric temperature, tropospheric water vapor, and stratospheric temperature can be accurately quantified from the combined data types, with relative errors in their global mean values being less than 4%, 10%, 15%, and 20%, respectively.

scholarly journals Reply to: "Tropical cirrus and water vapor: an effective Earth infrared iris feedback?"

2002 ◽  
Vol 2 (2) ◽  
pp. 99-101 ◽  
Author(s):  
M.-D. Chou ◽  
R. S. Lindzen ◽  
A. Y. Hou
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Water Vapor ◽  
Surface Temperature ◽  
Climate Sensitivity ◽  
Physical Meaning ◽  
Radiative Forcing ◽  
Sea Surface ◽  
Boundary Layer Clouds ◽  
High Level

Abstract. In assessing the iris effect suggested by Lindzen et al. (2001), Fu et al. (2002) found that the response of high-level clouds to the sea surface temperature had an effect of reducing the climate sensitivity to external radiative forcing, but the effect was not as strong as LCH found. The approach of FBH to specifying longwave emission and cloud albedos appears to be inappropriate, and the derived cloud optical properties may not have real physical meaning. The cloud albedo calculated by FBH is too large for cirrus clouds and too small for boundary layer clouds, which underestimates the iris effect.

scholarly journals Reply to: “Tropical cirrus and water vapor: an effective Earth infrared iris feedback?"

2002 ◽  
Vol 2 (1) ◽  
pp. 173-180 ◽  
Author(s):  
M.-D. Chou ◽  
R. S. Lindzen ◽  
A. Y. Hou
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Water Vapor ◽  
Surface Temperature ◽  
Climate Sensitivity ◽  
Physical Meaning ◽  
Radiative Forcing ◽  
Sea Surface ◽  
Boundary Layer Clouds ◽  
High Level

Abstract. In assessing the iris effect suggested by Lindzen et al. (2001), Fu et al. (2001, 2002) found that the response of high-level clouds to the sea surface temperature had an effect of reducing the climate sensitivity to external radiative forcing, but the effect was not as strong as Lindzen et al. (2001) found. The approach of Fu et al. (2001, 2002) to specifying longwave emission and cloud albedos appears to be inappropriate, and the derived cloud optical properties may not have real physical meaning. The cloud albedo calculated by Fu et al. (2001, 2002) is too large for cirrus clouds and too small for boundary layer clouds, which underestimates the iris effect.

scholarly journals Testing Climate Models Using Thermal Infrared Spectra

2008 ◽  
Vol 21 (9) ◽  
pp. 1863-1875 ◽  
Author(s):  
Stephen Leroy ◽  
James Anderson ◽  
John Dykema ◽  
Richard Goody
Keyword(s):  
Time Series ◽  
Water Vapor ◽  
Climate Models ◽  
Tropospheric Temperature ◽  
Strong Constraint ◽  
Detection Techniques ◽  
Clear Sky ◽  
Stratospheric Temperature ◽  
Occultation Data ◽  
The Tropics

Abstract An approach to test climate models with observations is presented. In this approach, it is possible to directly observe the longwave feedbacks of the climate system in time series of annual average outgoing longwave spectra. Tropospheric temperature, stratospheric temperature, water vapor, and carbon dioxide have clear and distinctive signatures in the infrared spectrum, and it is possible to detect trends of these signals unambiguously from trends in the outgoing longwave spectrum by optimal detection techniques. This approach is applied to clear-sky data in the tropics simulated from the output of an ensemble of climate models. Estimates of the water vapor–longwave feedback by this approach agree to within estimated errors with truth, and it is likely that an uncertainty of 50% can be obtained in 20 yr of a continuous time series. The correlation of tropospheric temperature and water vapor anomalies can provide a constraint on the water vapor–longwave feedback to 5% uncertainty in 20 yr, or 7% in 10 yr. Thus, it should be possible to place a strong constraint on climate models, which currently show a range of 30% in the water vapor–longwave feedback, in just 10 yr. These results may not hold in the presence of clouds, however, and so it may be necessary to supplement time series of outgoing longwave spectra with GPS radio occultation data, which are insensitive to clouds.

scholarly journals Observed HIRS and Aqua MODIS Thermal Infrared Moisture Determinations in the 2000s

2021 ◽  
Vol 13 (3) ◽  
pp. 502
Author(s):  
Eva E. Borbas ◽  
Paul W. Menzel
Keyword(s):  
Water Vapor ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Statistical Regression ◽  
Absorption Bands ◽  
Mean Values ◽  
Brightness Temperatures ◽  
Spectral Bands ◽  
Infrared Spectral ◽  
Moderate Resolution

This paper compares the tropospheric moisture data records derived from High-resolution Infrared Radiation Sounder (HIRS) and Moderate Resolution Imaging Spectro-radiometer (MODIS) measurements from the years 2003 through 2013. Total Precipitable Water Vapor (TPW) and Upper Tropospheric Precipitable Water Vapor (UTPW) are derived using the infrared spectral bands in the CO2 and H2O absorption bands as well as in the atmospheric windows. Retrieval of TPW and UTPW uses a statistical regression algorithm performed using clear sky radiances (and Brightness Temperatures) measured over land and ocean for both day and night. The TPW and UTPW seasonal cycles of HIRS and MODIS observations are found to be in synchronization with zonal mean values for one degree latitude bands within 2.0 mm and 0.07 mm, respectively.

scholarly journals A new multispectral photometer for monitoring aerosol microphysical, optical, and radiative properties

2021 ◽  
Author(s):  
Yu Zheng ◽  
Huizheng Che ◽  
Yupeng Wang ◽  
Xiangao Xia ◽  
Xiuqing Hu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Radiative Forcing ◽  
Integrated Design ◽  
Single Scattering ◽  
Radiative Properties ◽  
Mean Values ◽  
Smart Control ◽  
Fine Mode

Abstract. A new multispectral photometer, named CW193, was proposed in this study for monitoring aerosol microphysical, optical, and radiative properties. The instrument has a highly integrated design, smart control performance, and is composed of three parts (an optical head, a robotic drive platform, and a stents system). Because of its low maintenance requirements, this instrument is appropriate for the deployment in remote and unpopulated regions. Based on the synchronous measurements, the CW193 products was validated using reference data from the AERONET CE318 photometer. The results show that the raw digital counts from CW193 agree well the counts from AERONET (R2 > 0.97), with daily average triplets of around 1.2 % to 3.0 % for the ultraviolet band and less than 2.0 % for the visible and infrared bands. A good aerosol optical depth agreement (R > 0.99, 100 % within expected error) and root mean square error (RMSE) values ranging from 0.006 (for the 870 nm band) to 0.016 (for 440 nm the band) are obtained, with a relative mean bias (RMB) ranging from 0.922 to 1.112 and an aerosol optical depth bias within ±0.04. The maximum deviations for fine-mode particles varied from about 8.9 % to 77.6 %, whereas the variation for coarse-mode particles was about 13.1 % to 29.1 %. The deviation variations of the single scattering albedo were approximately 0.1–1.8 %, 0.6–1.9 %, 0.1–2.6 %, and 0.8–3.5 % for the 440 nm, 675 nm, 870 nm, and 1020 nm bands, respectively. For the aerosol direct radiative forcing, deviations of approximately 4.8–12.3 % was obtained at the Earth’s surface and 5.4–15.9 % for the top of the atmosphere. In addition, the water vapor retrievals showed a satisfactory accuracy, characterized by a high R value (~0.997), a small RMSE (~0.020), and good expected error distribution (100 % within expected error). The water vapor RMB was about 0.979 and the biases mostly varied within ±0.04, whereas the mean values were concentrated within ±0.02.

Effectiveness of Brushing Associated with Oral Irrigation in Maintenance of Peri-Implant Tissues and Overdentures: Clinical Parameters and Patient Satisfaction.

2020 ◽  
Author(s):  
Marcela Moreira Salles ◽  
Viviane de Cássia Oliveira ◽  
Ana Paula Macedo ◽  
Claudia Helena Silva-Lovato ◽  
Helena de Freitas Oliveira Paranhos
Keyword(s):  
Patient Satisfaction ◽  
Analogue Scale ◽  
Ring System ◽  
Complete Dentures ◽  
Gingival Index ◽  
Prosthetic Rehabilitation ◽  
Mean Values ◽  
Probing Depth ◽  
Significant Difference ◽  
High Level

Implant-supported prostheses hygiene and peri-implant tissues health are considered to be predictive factors for successful prosthetic rehabilitation. Therefore, the purpose of this study was to evaluate the effectiveness of brushing associated with oral irrigation measured as biofilm-removing capacity, maintenance of healthy oral tissues, and patient satisfaction. A randomized, crossover clinical trial was conducted with 38 patients who wore conventional maxillary complete dentures and mandibular overdentures retained by the O-ring system. The patients were instructed to use the following hygiene methods for 14 days: mechanical brushing [MB (brush and dentifrice - Control)]; and MB with oral irrigation [WP (Waterpik - Experimental)]. Biofilm-removing capacity and maintenance of healthy oral tissues were evaluated by the Modified Plaque Index (PI), Gingival Index (GI), Probing Depth (PD), and Bleeding on Probing Index (BP) recorded at baseline and after each method. In parallel, patients answered a specific questionnaire using a Visual Analogue Scale after each hygiene method. Data were analyzed by Friedman and Wilcoxon tests (α=0.05). The results showed significantly lower PI, GI, PD, and BP indices after application of the hygiene methods (P<0.001) than those observed at baseline. However, no significant difference was found between MB and WP. The satisfaction questionnaire responses to both methods showed high mean values for all questions, with no statistically significant difference found between the answers given after the use of MB and WP (P>0.05). The findings suggest that WP was effective in reducing PI, GI, PD, and BP indices and provided a high level of patient satisfaction.

scholarly journals Some ideas on data types in high level languages

1976 ◽  
Author(s):  
David Gries ◽  
Narain Gehani
Keyword(s):  
Data Types ◽  
High Level

scholarly journals Applying MRI Intensity Normalization on Non-Bone Tissues to Facilitate Pseudo-CT Synthesis from MRI

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 816
Author(s):  
Kuei-Yuan Hou ◽  
Hao-Yuan Lu ◽  
Ching-Ching Yang
Keyword(s):  
Mean Value ◽  
Tissue Type ◽  
Routine Practice ◽  
Intensity Level ◽  
Mean Values ◽  
Conversion Model ◽  
Ratio Image ◽  
Abdominal Mri ◽  
High Level ◽  
Intensity Normalization

This study aimed to facilitate pseudo-CT synthesis from MRI by normalizing MRI intensity of the same tissue type to a similar intensity level. MRI intensity normalization was conducted through dividing MRI by a shading map, which is a smoothed ratio image between MRI and a three-intensity mask. Regarding pseudo-CT synthesis from MRI, a conversion model based on a three-layer convolutional neural network was trained and validated. Before MRI intensity normalization, the mean value ± standard deviation of fat tissue in 0.35 T chest MRI was 297 ± 73 (coefficient of variation (CV) = 24.58%), which was 533 ± 91 (CV = 17.07%) in 1.5 T abdominal MRI. The corresponding results were 149 ± 32 (CV = 21.48%) and 148 ± 28 (CV = 18.92%) after intensity normalization. With regards to pseudo-CT synthesis from MRI, the differences in mean values between pseudo-CT and real CT were 3, 15, and 12 HU for soft tissue, fat, and lung/air in 0.35 T chest imaging, respectively, while the corresponding results were 3, 14, and 15 HU in 1.5 T abdominal imaging. Overall, the proposed workflow is reliable in pseudo-CT synthesis from MRI and is more practicable in clinical routine practice compared with deep learning methods, which demand a high level of resources for building a conversion model.

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