Relative water content may be accurately estimated using the ratio of tissue fresh weight to tissue turgid weight, termed here relative tissue weight. That relative water content and relative tissue weight are linearly related is demonstrated algebraically. The mean value of r2 for grapevine (Vitis vinifera L. cv. Shiraz) leaf tissue over eight separate sampling occasions was 0.993. Similarly high values were obtained for maize (Zea mays cv. Cornell M-3) (0.998) and apple (Malus sylvestris cv. Northern Spy) (0.997) using a range of leaf ages. The proposal by Downey and Miller (1971. Rapid measurements of relative turgidity in maize (Zea mays L.). New Phytol. 70: 555-560) that relative water content in maize may be estimated from water uptake was also investigated for grapevine leaves; this was found to be a less reliable estimate than that obtained with relative tissue weight. With either method, there is a need for calibration, although this could be achieved for relative tissue weight at least with only a few subsamples.The relative water content technique, formerly known as relative turgidity, was originally described by Weatherley (9, 10) and has been widely accepted as a reproducible and meaningful index of plant water status (see literature cited by Barrs [1] monly expressed in decimal form (5, 11), and this convention is followed here.A major disadvantage of the RWC technique is the considerable time lag between sampling and obtaining the result. Further, the four weighing operations required (one for tare weight) are time-consuming and monotonous. These objections could be partly overcome if the oven-drying operation and subsequent weighing operation could be eliminated. However, this would require that RWC could be reliably estimated from the prior weights: sampling weight, turgid weight, or the difference, water uptake. Downey and Miller (3) have determined an empirical relationship between RWC and water uptake for maize, using small discs of constant area.A second indirect estimate of RWC is introduced here. This index, termed relative tissue weight, is calculated as the ratio tissue fresh weight to turgid weight. The same ratio has been used before (4,7,8), but in all three instances it has been termed erroneously relative turgidity. MATERIALS AND METHODSGrapevines (Vitis vinifera L. cv. Shiraz) growing in an irrigation trial at the Griffith Viticultural Research Station, N.S.W. provided a range of leaf material of varying water status. Two replicates of eight treatments were sampled on each of 2 consecutive days on eight occasions throughout the growing season of 1968-69. The youngest fully expanded leaf was used. Four leaf samples were taken from each plot of four adjacent vines between 6 AM and 6:30 AM EST, sealed in plastic bags, and taken to the laboratory. There an entire disc of 8.4 cm diameter was cut from each leaf. Discs of this size were found to give considerably less variable RWC values than samples of 20 discs of diameter 0.8 cm, as recommended by Barrs (1); RWC values for th...

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The Cross‐Track Infrared Sounder (CrIS) is a Fourier Transform Michelson interferometer instrument launched on board the Suomi National Polar‐Orbiting Partnership (Suomi NPP) satellite on 28 October 2011. CrIS provides measurements of Earth view interferograms in three infrared spectral bands at 30 cross‐track positions, each with a 3 × 3 array of field of views. The CrIS ground processing software transforms the measured interferograms into calibrated and geolocated spectra in the form of Sensor Data Records (SDRs) that cover spectral bands from 650 to 1095 cm−1, 1210 to 1750 cm−1, and 2155 to 2550 cm−1 with spectral resolutions of 0.625 cm−1, 1.25 cm−1, and 2.5 cm−1, respectively. During the time since launch a team of subject matter experts from government, academia, and industry has been engaged in postlaunch CrIS calibration and validation activities. The CrIS SDR product is defined by three validation stages: Beta, Provisional, and Validated. The product reached Beta and Provisional validation stages on 19 April 2012 and 31 January 2013, respectively. For Beta and Provisional SDR data, the estimated absolute spectral calibration uncertainty is less than 3 ppm in the long‐wave and midwave bands, and the estimated 3 sigma radiometric uncertainty for all Earth scenes is less than 0.3 K in the long‐wave band and less than 0.2 K in the midwave and short‐wave bands. The geolocation uncertainty for near nadir pixels is less than 0.4 km in the cross‐track and in‐track directions.

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Abstract. The METOP-A satellite Infrared AtmosphericSounding Interferometer (IASI) Level 2 products comprise retrievals of vertical profiles of temperature and water vapor. The error covariance matrices and biases of the most recent version (4.3.1) of the L2 data were assessed, and the assessment was validated using radiosonde data for reference. The radiosonde data set includes dedicated and synoptic time launches at the Lindenberg station in Germany. For optimal validation, the linear statistical Validation Assessment Model (VAM) was used. The VAM uses radiosonde profiles as input and provides optimal estimate of the nominal IASI retrieval by utilizing IASI averaging kernels and statistical characteristics of the ensembles of the reference radiosondes. For temperatures above 900 mb and water retrievals above 700 mb, level expected and assessed errors are in good agreement. Below those levels, noticeable excess in assessed error is observed, possibly due to inaccurate surface parameters and undetected clouds/haze.

It has become of interest to study long‐term effects of CO2 concentration on plant growth, because intensive burning of fossil fuels and destruction of forests promise to continue the recent rise in atmospheric partial pressures of CO2 into the next century (Bolin, 1977; Stuiver, 1978). Effects of CO2 enrichment on growth of crop and forest species were therefore studied for the first time in the field in open top exposure chambers at daytime mean CO2 concentrations of 612, 936, 1292, and 1638 mg m−3, and in ambient control plots. Increased growth of plant parts of corn (Zea mays L. ‘Golden Bantam’), soybean [Glycine max L. (Merr.) ‘Ransom’], loblolly pine (Pinus taeda L.), and sweetgum (Liquidambar styraciflua L.) were recorded. Growth increases for soybean and sweetgum in elevated CO2 atmospheres were due to increases in leaf area and photosynthesis per unit leaf area, and decreases in conductance and, therefore, water use. For corn, however, photosynthesis was unaffected by CO2 enhancement, and growth stimulation appeared to be due to lowered conductance and increased water use efficiency alone.

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The effects of atmospheric carbon dioxide on corn, soybeans, loblolly pine, and sweetgum were studied in the field during a growing season. The plants were exposed to a range of concentrations of carbon dioxide day and night in open-topped, flow-through chambers. At a mean daytime carbon dioxide concentration of 910 parts per million, increases in total biomass ranged from 157 to 186 percent of the control values. Seed yield and wood volume increased and there were changes in plant anatomy and form. Net photosynthesis increased with increasing carbon dioxide concentration in soybeans and sweetgum, but was unaffected in corn. Water use efficiency also increased in corn, soybeans, and sweetgum.