Beschreibung: The Ny-Ålesund Ozone Monitoring Intercomparison (NAOMI) took place at Ny-Ålesund,Spitsbergen (78.92 degrees N, 11.95 degrees E), from January 20 to February 10, 1998.This paper focuses on comparing stratospheric ozone profiles measured by the Alfred WegenerInstitute differential absorption lidar (AWI DIAL), in routine Network for Detection ofStratospheric Change (NDSC) operation at Ny-Ålesund, the mobile Goddard Space Flight CenterDIAL (GSFC DIAL), the University of Bremen microwave radiometer (mu Wave), andelectrochemical concentration cell (ECC) ozonesondes, flown routinely by AWI. Below 30 km thetwo DIALs and the ECC sondes give virtually the same results, with instrumental precision(repeatability) better than +/-5% and no detectable bias. When their coarser altitude resolution isnot accounted for, the mu Wave data show 15% low bias at 16 km and 15% high bias at 23 km,Considerably better agreement, better than +/-5% around 20 km and above 30 km, is found whenthe altitude resolution of the other data is degraded to match that of the mu Wave. During NAOMIthe mu Wave data show high bias of up to 10% in a mixing ratio plateau around 25 km. Such biashas not been seen in routine intercomparisons between mu Wave and ECC sonde data atNy-Ålesund. It is likely caused by an a priori profile 40% higher than the true profile duringNAOMI, Above 30 km the mu Wave data show the best precision (repeatability), about +/-3 to+/-5%. Precision of the GSFC DIAL data decreases from better than +/-5% at 30 km to about+/-10% at 40 km, and the precision for the AWI DIAL data decreases from better than +/-5% at30 km to +/-30% at 40 km. From 34 to 38 km the AWI profile is 12% lower than the GSFCprofile. AWI DIAL measurements that are low at 35 km often end below 40 km of show highvalues at 40 or 45 km, This behavior seems related to the way in which the AWI processingalgorithm changes altitude resolution for data with poor signal-to-noise ratio.

Beschreibung: An intercomparison of ozone differential absorption lidar algorithms was performed in 1996within the framework of the Network for the Detection of Stratospheric Changes (NDSC) lidarworking group. The objective of this research was mainly to test the differentiating techniquesused by the various lidar teams involved in the NDSC for the calculation of the ozone numberdensity from the lidar signals. The exercise consisted of processing synthetic lidar signalscomputed from simple Rayleigh scattering and three initial ozone profiles. Two of these profilescontained perturbations in the low and the high stratosphere to test the vertical resolution of thevarious algorithms. For the unperturbed profiles the results of the simulations show thecorrect behavior of the lidar processing methods in the low and the middle stratosphere withbiases of less than 1% with respect to the initial profile to as high as 30 km in most cases. In theupper stratosphere, significant biases reaching 10% at 45 km for most of the algorithms areobtained. This bias is due to the decrease in the signal-to-noise ratio with altitude, which makes itnecessary to increase the number of points of the derivative low-pass filter used for dataprocessing. As a consequence the response of the various retrieval algorithms to perturbations inthe ozone profile is much better in the lower stratosphere than in the higher range. These resultsshow the necessity of limiting the vertical smoothing in the ozone lidar retrieval algorithm andquestions the ability of current lidar systems to detect long-term ozone trends above 40 km.Otherwise the simulations show in general a correct estimation of the ozone profile random errorand, as shown by the tests involving the perturbed ozone profiles, some inconsistency in theestimation of the vertical resolution among the lidar teams involved in this experiment.

Beschreibung: Salmon produced by hatcheries have lower fitness in the wild than naturally produced salmon, but the factors underlying this difference remain an active area of research. We used genetic parentage analysis of alevins produced by experimentally mixed groups of wild and hatchery coho salmon ( Oncorhynchus kisutch ) to quantify male paternity in spawning hierarchies. We identify factors influencing paternity and revise previously published behavioural estimates of reproductive success for wild and hatchery males. We observed a strong effect of hierarchy size and hierarchy position on paternity: in two-male hierarchies, the first male sired 63% (±29%; s.d.) of the alevins and the second male 37% (±29%); in three-male hierarchies, the first male sired 64% (±26%), the second male 24% (±20%) and the third male 12% (±10%). As previously documented, hatchery males hold inferior positions in spawning hierarchies, but we also discovered that hatchery males had only 55–84% the paternity of wild males when occupying the same position within a spawning hierarchy. This paternity difference may result from inferior performance of hatchery males during sperm competition, female mate choice for wild males, or differential offspring survival. Regardless of its cause, the combination of inferior hierarchical position and inferior success at a position resulted in hatchery males having only half (51%) the reproductive success of wild males.