The effect of spatial variability of the atmospheric CO sub(2) distribution on temperature and water vapor retrievals from high spectral resolution observations of infrared emission is estimated by ...performing 4 different retrieval experiments. Using a global mean CO sub(2) value, as currently routinely used, introduces errors in the retrieved temperature profile of up to 0.85 K compared to a retrieval in which the CO sub(2) profile is known exactly. Including CO sub(2) in the retrieval vector reduces these errors to 0.3 K. A more practical alternative, especially for data assimilation, is to use a monthly mean zonal mean CO sub(2) value, which produces errors of up to 0.35 K in the temperature profile.
ABSTRACT
Methods
A questionnaire was administered to 958 women attending the antenatal clinic at Mercy Hospital for Women, Melbourne, to ascertain their choice of title during pregnancy. Midwifery, ...nursing and medical staff (376 in total) were also invited to respond to a similar questionnaire.
Results
The response rate was 73.6% from the survey of all women who were overwhelmingly in favour of being called ‘patient’ as their first choice (34%), followed by ‘other’ (20%) and then ‘mother’ (19%). Virtually all women requesting ‘other’ wished to be called by their name. Women wishing to be called ‘patient’ for first choice did not significantly differ from the remainder of the study group in age, gestation, number of previous pregnancies, or number of children. When women from the Family Birth Centre (FBC) were analysed as a separate group, they had a clear preference to be called ‘other’ (unanimously, by their name) than the general antenatal population (odds ratio (OR) 5.1; 95% confidence interval (CI) 3.1, 8.3; p < 0.0001). The staff survey, with a response rate of 84%, also demonstrated that ‘patient’ was the most popular first choice for patient title. Medical staff were significantly more likely to choose ‘patient’ (OR 4.2, 95% CI 2.3, 7.7; p < 0.0001), though the term ‘patient’ was the preferred choice of all staff.
Precision requirements are determined for space-based column-averaged CO sub(2) dry air mole fraction (XCO sub(2)) data. These requirements result from an assessment of spatial and temporal gradients ...in XCO sub(2), the relationship between XCO sub(2) precision and surface CO sub(2) flux uncertainties inferred from inversions of the XCO sub(2) data, and the effects of XCO sub(2) biases on the fidelity of CO sub(2) flux inversions. Observational system simulation experiments and synthesis inversion modeling demonstrate that the Orbiting Carbon Observatory mission design and sampling strategy provide the means to achieve these XCO sub(2) data precision requirements.
We evaluated how climate influences interannual variability in the terrestrial Net Ecosystem Exchange (NEE) of CO sub(2) using the Simple Biosphere Model, Version 2 (SiB2) for 1983 to 1993 on a ...global, 1 degree by 1 degree latitude/longitude grid with a 10-min time step. We quantified climate influences on NEE, explained regional differences, and related NEE variability to the Arctic Oscillation (AO) and the El Nino-Southern Oscillation (ENSO). The simulated NEE reproduces the salient features and magnitude of the measured global CO sub(2) growth rate. The Northern Hemisphere shows a pattern of alternating positive and negative NEE anomalies that cancel such that the tropics dominate the global simulated NEE interannual variability. Climate influences have strong regional differences with precipitation dominating in the tropics and temperature in the extratropics. In tropical regions with drier soils, precipitation control of photosynthesis (i.e., drought stress) dominates; in nearly saturated soils, precipitation control of respiration dominates. Because of cancellation and competing effects, no single climate variable controls global or regional NEE interannual variability. Globally, precipitation accounts for 44% of NEE variability; followed by Leaf Area Index (23%), soil carbon (12%), and temperature (16%). The influence of ENSO on NEE variability is consistent with that expected for shifting precipitation patterns in the tropics. Except in northern Europe, temperature advection by the AO does not significantly influence NEE variability. Neither the AO nor ENSO fully explain the temperature influence on respiration or the simulated NEE anomaly pattern in the Northern Hemisphere.
Monthly CO sub(2) fluxes are estimated across 1988-2003 for 22 emission regions using data from 78 CO sub(2) measurement sites. The same inversion (method, priors, data) is performed with 13 ...different atmospheric transport models, and the spread in the results is taken as a measure of transport model error. Interannual variability (IAV) in the winds is not modeled, so any IAV in the measurements is attributed to IAV in the fluxes. When both this transport error and the random estimation errors are considered, the flux IAV obtained is statistically significant at P <= 0.05 when the fluxes are grouped into land and ocean components for three broad latitude bands, but is much less so when grouped into continents and basins. The transport errors have the largest impact in the extratropical northern latitudes. A third of the 22 emission regions have significant IAV, including the Tropical East Pacific (with physically plausible uptake/release across the 1997-2000 el Nino/La Nina) and Tropical Asia (with strong release in 1997/1998 coinciding with large-scale fires there). Most of the global IAV is attributed robustly to the tropical/southern land biosphere, including both the large release during the 1997/1998 el Nino and the post-Pinatubo uptake.
This paper investigates the expected capabilities of the new generation of infrared satellite sounders for detecting CO2. A general circulation model is used to simulate realistic CO2 fields and to ...define the needed accuracy of CO2 observations in order to be useful in constraining surface sources and sinks of CO2. Optimal estimation retrieval theory is then used to determine the possible accuracy of the satellite measurements and to define the retrieval characteristics. A discussion of several factors that affect the retrievals is also included. We conclude that tropospheric column retrievals of CO2 are possible with an accuracy of better than 1 ppmv on a monthly mean basis. Several factors, like thin cirrus clouds and radiative transfer modeling errors, will degrade these results if not carefully accounted for. The possibility of extensive time and spatial averaging of the satellite observations will overcome some of these problems. (Author)
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