On-board Direct CO2 Flux Measurement Technique over the Open Ocean

2008 ◽  
Author(s):  
F. Kondo ◽  
O. Tsukamoto ◽  
H. Ishida ◽  
K. Yoneyama
Keyword(s):  
Measurement Technique ◽  
Flux Measurement ◽  
Open Ocean

scholarly journals Measurements of ambient HONO concentrations and vertical HONO flux above a northern Michigan forest canopy

2012 ◽  
Vol 12 (17) ◽  
pp. 8285-8296 ◽  
Author(s):  
N. Zhang ◽  
X. Zhou ◽  
S. Bertman ◽  
D. Tang ◽  
M. Alaghmand ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Forest Canopy ◽  
Sonic Anemometer ◽  
Flux Measurement ◽  
Measurement Systems ◽  
Ambient Concentration ◽  
Solar Noon ◽  
Absorption Photometer ◽  
Upward Flux ◽  
Northern Michigan

Abstract. Systems have been developed and deployed at a North Michigan forested site to measure ambient HONO and vertical HONO flux. The modified HONO measurement technique is based on aqueous scrubbing of HONO using a coil sampler, followed by azo dye derivatization and detection using a long-path absorption photometer (LPAP). A Na2CO3-coated denuder is used to generate "zero HONO" air for background correction. The lower detection limit of the method, defined by 3 times of the standard deviation of the signal, is 1 pptv for 1-min averages, with an overall uncertainty of ±(1 + 0.05 [HONO]) pptv. The HONO flux measurement technique has been developed based on the relaxed eddy accumulation approach, deploying a 3-D sonic anemometer and two HONO measurement systems. The overall uncertainty is estimated to be within ±(8 × 10−8 + 0.15 FHONO) mol m−2 h−1, with a 20-min averaged data point per 30 min. Ambient HONO and vertical HONO flux were measured simultaneously at the PROPHET site from 17 July to 7 August 2008. The forest canopy was found to be a net HONO source, with a mean upward flux of 0.37 × 10−6 moles m−2 h−1. The HONO flux reached a maximal mean of ~0.7 × 10−6 moles m−2 h−1 around solar noon, contributing a major fraction to the HONO source strength required to sustain the observed ambient concentration of ~70 pptv. There were no significant correlations between [NOx] and daytime HONO flux and between JNO2 × [NO2] and HONO flux, suggesting that NOx was not an important precursor responsible for HONO daytime production on the forest canopy surface in this low-NOx rural environment. Evidence supports the hypothesis that photolysis of HNO3 deposited on the forest canopy surface is a major daytime HONO source.

scholarly journals Measurements of ambient HONO concentrations and vertical HONO flux above a northern Michigan forest canopy

2012 ◽  
Vol 12 (3) ◽  
pp. 7273-7304 ◽  
Author(s):  
N. Zhang ◽  
X. Zhou ◽  
S. Bertman ◽  
D. Tang ◽  
M. Alaghmand ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Forest Canopy ◽  
Sonic Anemometer ◽  
Flux Measurement ◽  
Rural Environment ◽  
Measurement Systems ◽  
Ambient Concentration ◽  
Solar Noon ◽  
Upward Flux ◽  
Northern Michigan

Abstract. Systems have been developed and deployed at a North Michigan forested site to measure ambient HONO and vertical HONO flux. The modified HONO measurement technique is based on aqueous scrubbing of HONO using a coil sampler, followed by azo dye derivatization and detection using an optical fiber spectrometer with a 1-m long path flow cell. A Na2CO3-coated denuder is used to generate "zero HONO" air for background correction. The lower detection limit of the method, defined by 3 times of the standard deviation of the signal, is 1 pptv for 2-min averages, with an overall uncertainty of ±(1 + 0.05 [HONO]) pptv. The HONO flux measurement technique has been developed based on the relaxed eddy accumulation approach, deploying a 3-D sonic anemometer and two HONO measurement systems. The overall uncertainty is estimated to be within ±(8 × 10−8 + 0.15 FHONO) mol m−2 h−1, with a 20-min averaged data point per 30 min. Ambient HONO and vertical HONO flux were measured simultaneously at the PROPHET site from 17 July to 7 August 2008. The forest canopy was found to be a net HONO source, with a mean upward flux of 0.37 × 10−6 moles m−2 h−1. The HONO flux reached a maximum mean of ~0.7 × 10−6 moles m−2 h−1 around solar noon, contributing a major fraction (~60%) to the HONO source strength required to sustain the observed ambient concentration of ~70 pptv. There was no significant correlation between NOx and daytime HONO flux, suggesting that NOx was not an important precursor responsible for HONO daytime production on the forest canopy surface in the low-NOx rural environment. Evidence suggests that photolysis of HNO3 deposited on the forest canopy surface is a major daytime HONO source.

scholarly journals On-board Automated Eddy Flux Measurement System over Open Ocean

SOLA ◽  
2005 ◽  
Vol 1 ◽  
pp. 37-40 ◽  
Author(s):  
Satoshi Takahashi ◽  
Fumiyoshi Kondo ◽  
Osamu Tsukamoto ◽  
Yoshiki Ito ◽  
Seigo Hirayama ◽  
...  
Keyword(s):  
Measurement System ◽  
Flux Measurement ◽  
Open Ocean ◽  
Eddy Flux

Heat flux measurement techniques

1999 ◽  
Vol 213 (7) ◽  
pp. 655-677 ◽  
Author(s):  
P R N Childs ◽  
J R Greenwood ◽  
C A Long
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Measurement Technique ◽  
Measurement Techniques ◽  
Flux Measurement ◽  
Thin Film Deposition ◽  
Temperature Sensors ◽  
Film Deposition ◽  
Heat Flux Measurement

Heat flux measurement is used in the field of fluid mechanics and heat transfer to quantify the transfer of heat within systems. Several techniques are in common use, including: differential temperature sensors such as thermopile, layered resistance temperature devices or thermocouples and Gardon gauges; calorimetric methods involving a heat balance analysis and transient monitoring of a representative temperature, using, for example, thin-film temperature sensors or temperature sensitive liquid crystals; energy supply or removal methods using, for example, a heater to generate a thermal balance; and, finally, by measurement of mass transfer which can be linked to heat transfer using the analogy between the two. No one method is suitable to all applications because of the differing considerations of accuracy, sensitivity, size, cost and robustness. Recent developments including the widespread availability and application of thin-film deposition techniques for metals and ceramics, allied with advances in microtechnology, have expanded the range of devices available for heat flux measurement. This paper reviews the various types of heat flux sensors available, as well as unique designs for specific applications. Critical to the use of a heat flux measurement technique is accurate calibration. Use of unmatched materials disturbs the local heat flux and also the local convective boundary layer, producing a potential error that must be compensated for. The various techniques in common use for calibration are described. A guide to the appropriate selection of a heat flux measurement technique is provided according to the demands of response, sensitivity, temperature of operation, heat flux intensity, manufacturing constraints, commercial availability, cost, thermal disturbance and acceleration capability for vibrating, rotating and reciprocating applications.

Analysis of Neutron Flux Measurement in Thai Research Reactor-1/Modification 1 Using the Monte Carlo Method

2014 ◽  
Vol 979 ◽  
pp. 23-26
Author(s):  
S. Sabaibang ◽  
S. Lekchaum ◽  
C. Tippayakul
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Neutron Flux ◽  
Measurement Technique ◽  
Flux Distribution ◽  
Research Reactor ◽  
Gold Foil ◽  
Flux Measurement ◽  
Foil Thickness ◽  
The Monte Carlo Method

This study adopts the Monte Carlo method to analyze the neutron flux measurement technique in Thai Research Reactor-1/Modification 1(TRR-1/M1) by performing simulations using MCNPX computer program. The neutron flux measurement technique being analyzed is called “gold foil activation technique”. The simulation model consists of gold foil located in the middle of in-core irradiation which is in the center of the reactor core. The variation in the calculated neutron flux is assessed by varying the gold foil thickness from approximately 500 – 800 μcm. It is found from the simulation that the calculated neutron flux can differ by 33 % when increasing the gold foil thickness by 60%. In addition, more detailed simulations to determine neutron flux distribution within the gold foil are performed to study and explain the variation in neutron flux calculated at different foil thicknesses. The simulation result shows that self-shielding effect has significant impact to the neutron flux distribution within the gold foil, and hence to the average neutron flux.

Sign in / Sign up

Export Citation Format

Share Document