scholarly journals Long-term observation of mid-latitude quasi 2-day waves by a water vapor radiometer

2018 ◽  
Author(s):  
Martin Lainer ◽  
Klemens Hocke ◽  
Niklaus Kämpfer
Keyword(s):  
Water Vapor ◽  
Large Fraction ◽  
Dynamical Behavior ◽  
Measurement Data ◽  
Data Set ◽  
Water Vapor Radiometer ◽  
Long Term Observation ◽  
Scientific Value ◽  
High Degree

Abstract. A mesospheric water vapor data set obtained by the middle atmospheric water vapor radiometer (MIAWARA) close to Bern, Switzerland (46.88° N, 7.46° E) during October 2010 to September 2017 is investigated to study the long-term evolution and variability of quasi 2-day waves (Q2DWs). We present a climatological overview and an insight on the dynamical behavior of these waves with the occurring spectrum of periods as seen from a mid-latitude observation site. Such a large and nearly continuous measurement data set as ours is rare and of high scientific value. The core results of our investigation include that the activity of the Q2DW manifests in burst-like events and is higher during winter months (November–February) than during summer months (May–August) for the altitude region of the mesosphere (up to 0.02 hPa in winter and up to 0.05 hPa in summer) that is accessible for the instrument. Single Q2DW events reach at most about 0.8 ppm in the H2O amplitudes. Further, monthly mean Q2DW amplitude spectra are presented and reveal a high frequency variability between different months. A large fraction of identified Q2DW events (20 %) develop periods between 38–40 h. Further, we show the temporal evolution of monthly mean Q2DW oscillations continuously for all months and separated for single months over 7 years. The analysis of autobicoherence spectra gives evidence that the Q2DW occasionally is to a high degree phase coupled to diurnal oscillations and to waves with a period close to 18 h.

scholarly journals Long-term observation of midlatitude quasi 2-day waves by a water vapor radiometer

2018 ◽  
Vol 18 (16) ◽  
pp. 12061-12074 ◽  
Author(s):  
Martin Lainer ◽  
Klemens Hocke ◽  
Niklaus Kämpfer
Keyword(s):  
Water Vapor ◽  
Large Fraction ◽  
Dynamical Behavior ◽  
Measurement Data ◽  
Data Set ◽  
Water Vapor Radiometer ◽  
Long Term Observation ◽  
Scientific Value ◽  
High Degree

Abstract. A mesospheric water vapor data set obtained by the middle atmospheric water vapor radiometer (MIAWARA) close to Bern, Switzerland (46.88∘ N, 7.46∘ E) during October 2010 to September 2017 is investigated to study the long-term evolution and variability of quasi 2-day waves (Q2DWs). We present a climatological overview and an insight on the dynamical behavior of these waves with the occurring spectrum of periods as seen from a midlatitude observation site. Such a large and nearly continuous measurement data set as ours is rare and of high scientific value. The core results of our investigation indicate that the activity of the Q2DW manifests in burst-like events and is higher during winter months (November–February) than during summer months (May–August) for the altitude region of the mesosphere (up to 0.02 hPa in winter and up to 0.05 hPa in summer) accessible for the instrument. Single Q2DW events reach at most about 0.8 ppm in the H2O amplitudes. Further, monthly mean Q2DW amplitude spectra are presented and reveal a high-frequency variability between different months. A large fraction of identified Q2DW events (20 %) develop periods between 38 and 40 h. Further, we show the temporal evolution of monthly mean Q2DW oscillations continuously for all months and separated for single months over 7 years. The analysis of autobicoherence spectra gives evidence that Q2DWs are sometimes phase coupled to diurnal oscillations to a high degree and to waves with a period close to 18 h.

Statistical Characteristics of Long-Term High-Resolution Precipitable Water Vapor Data at Darwin

2018 ◽  
Vol 10 (04) ◽  
pp. 1850010
Author(s):  
Kimberly Leung ◽  
Aneesh C. Subramanian ◽  
Samuel S. P. Shen
Keyword(s):  
Water Vapor ◽  
High Resolution ◽  
Southern Oscillation ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Statistical Characteristics ◽  
Convective Precipitation ◽  
Data Set ◽  
Best Estimates

This paper studies the statistical characteristics of a unique long-term high-resolution precipitable water vapor (PWV) data set at Darwin, Australia, from 12 March 2002 to 28 February 2011. To understand the convective precipitation processes for climate model development, the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) program made high-frequency radar observations of PWV at the Darwin ARM site and released the best estimates from the radar data retrievals for this time period. Based on the best estimates, we produced a PWV data set on a uniform 20-s time grid. The gridded data were sufficient to show the fractal behavior of precipitable water with Hausdorff dimension equal to 1.9. Fourier power spectral analysis revealed modulation instability due to two sideband frequencies near the diurnal cycle, which manifests as nonlinearity of an atmospheric system. The statistics of PWV extreme values and daily rainfall data show that Darwin’s PWV has El Nino Southern Oscillation (ENSO) signatures and has potential to be a predictor for weather forecasting. The right skewness of the PWV data was identified, which implies an important property of tropical atmosphere: ample capacity to hold water vapor. The statistical characteristics of this long-term high-resolution PWV data will facilitate the development and validation of climate models, particularly stochastic models.

ASM1 dynamic calibration and long-term validation for an intermittently aerated WWTP

2006 ◽  
Vol 53 (12) ◽  
pp. 247-256 ◽  
Author(s):  
A. Marquot ◽  
A.-E. Stricker ◽  
Y. Racault
Keyword(s):  
Treatment Plant ◽  
Simulation Software ◽  
Biological Nutrient Removal ◽  
Model Parameters ◽  
Dynamic Calibration ◽  
Biological Degradation ◽  
Data Set ◽  
Degree Of Confidence ◽  
High Degree

Activated sludge models, and ASM1 in particular, are well recognised and useful mathematical representations of the macroscopic processes involved in the biological degradation of the pollution carried by wastewater. Nevertheless, the use of these models through simulation software requires a careful methodology for their calibration (determination of the model parameters' values) and the validation step (verification with an independent data set). This paper presents the methodology and the results of dynamic calibration and validation tasks as a prior work to a modelling project for defining a reference guideline destined to French designers and operators. To reach these goals, a biological nutrient removal (BNR) wastewater treatment plant (WWTP) with intermittent aeration was selected and monitored for 2 years. Two sets of calibrated parameters are given and discussed. The results of the long-term validation task are presented through a 2-month simulation with lots of operation changes. Finally, it is concluded that, even if calibrating ASM1 with a high degree of confidence with a single set of parameters was not possible, the results of the calibration are sufficient to obtain satisfactory results over long-term dynamic simulation. However, simulating long periods reveals specific calibration issues such as the variation of the nitrification capacity due to external events.

Reference foF2 measurement data set for long-term temperate-latitude regional mapping

1995 ◽  
Vol 16 (1) ◽  
pp. 163-166 ◽  
Author(s):  
P.A. Bradley ◽  
S.S. Kouris ◽  
Th. Xenos ◽  
M.I. Dick
Keyword(s):  
Measurement Data ◽  
Regional Mapping ◽  
Temperate Latitude ◽  
Data Set

scholarly journals A Raman lidar at La Reunion (20.8° S, 55.5° E) for monitoring water vapor and cirrus distributions in the subtropical upper troposphere: preliminary analyses and description of a future system

2011 ◽  
Vol 4 (5) ◽  
pp. 6449-6496
Author(s):  
C. Hoareau ◽  
P. Keckhut ◽  
J.-L. Baray ◽  
L. Robert ◽  
Y. Courcoux ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cirrus Cloud ◽  
La Réunion ◽  
Raman Lidar ◽  
Data Set ◽  
Upper Troposphere ◽  
Future System ◽  
Rayleigh Lidar ◽  
Term Monitoring

Abstract. A ground based Rayleigh lidar has provided continuous observations of tropospheric water vapor profiles and cirrus cloud using a preliminary Raman channels setup on an existing Rayleigh lidar above La Reunion over the period 2002–2005. With this instrument, we performed a first measurement campaign of 350 independent water vapor profiles. A statistical study of the distribution of water vapor profiles is presented and some investigations concerning the calibration are discussed. The data set having several long acquisition measurements during nighttime, an analysis of the diurnal cycle of water vapor has also been investigated. Analysis regarding the cirrus clouds is presented and a classification has been performed showing 3 distinct classes. Based on these results, the characteristics and the design of a future lidar system to be implemented at the new Reunion Island altitude observatory (2200 m) for long-term monitoring is presented and numerical simulations of system performance have been realized to compare both instruments.

Mesospheric water vapor and D/H ratio at the Venus terminator from SOIR/VEx

2020 ◽  
Author(s):  
Arnaud Mahieux ◽  
Ann Carine Vandaele ◽  
Sarah Chamberlain ◽  
Valérie Wilquet ◽  
Séverine Robert ◽  
...  
Keyword(s):  
Water Vapor ◽  
Full Range ◽  
Lower Thermosphere ◽  
Temporal Variations ◽  
Mixing Ratio ◽  
Short Term ◽  
Data Set ◽  
Solar Occultation ◽  
Venus Express

<p>The Solar Occultation in the InfraRed (SOIR) instrument onboard Venus Express sounded the Venus mesosphere and lower thermosphere at the terminator using solar occultation technique between April 2006 and December 2014.</p><p>We report on the water vapor vertical distribution above the clouds and geo-temporal variations, observed during the full Venus Express mission. Water vapor profiles are sampled between 80 and 120 km, and calculations of the water vapor volume mixing ratio agrees with those from previous studies. Short term variations over several Earth days dominate the data set, with densities varying by up to a factor 19 over a 24 hr period. Similarly to what was found for other trace gases detected with the SOIR instrument, such as HCl, HF and SO<sub>2</sub>, no significant spatial or long term trends are observed.</p><p>287 water vapor vertical profiles obtained at the Venus terminator between 80 km and 120 km from August 2006 and September 2014 were analyzed for temporal and spatial abundance variations. Standard deviations are significantly smaller than the full range of volume mixing ratio values at all altitudes indicating that the variations are real.</p><p>The decrease in volume mixing ratio abundance below 100 km appears to be a common feature of most water vapor volume mixing ratio profiles and agrees with the decrease in water vapor reported in previous studies. Based on a very limited number of spectra, the variability of the water vapor VMR was found to be higher in the lower than in the upper mesosphere of Venus; this is in agreement with our observations as the standard deviation of the SOIR mean profile is the smallest at 100 km and increases with decreasing altitude.</p><p>No significant spatial variations or long term temporal variations are observed in the present data set in which short term variability masks all other possible trends. Our observations agree that short term (between 1 and 10 Earth days) variability is dominant.</p><p>We also report on simultaneous observations of the water first isotopologue HDO made by SOIR, which occurred 194 times during the whole VEx mission. Similarly to water vapor, we observe a large variation of HDO with time and space, without any clear time of spatial dependency.</p><p>We report on the ratio of the simultaneously measured HDO and H<sub>2</sub>O profiles, that show a constant ratio of 0.1 ± 0.1 below 100 km, and increase exponentially at higher altitude to reach a value of 1 ± 0.4 at 120 km of altitude. The results are in agreement with previous works below 100 km.</p>

scholarly journals Future Prospects of Helioseismology from Space

1990 ◽  
Vol 121 ◽  
pp. 289-304
Author(s):  
R.M. Bonnet
Keyword(s):  
Solar Cycle ◽  
Solar Interior ◽  
High Signal ◽  
Future Prospects ◽  
Solar Constant ◽  
Interior Space ◽  
Data Set ◽  
Solar Diameter ◽  
Long Term Observation

AbstractIn view of their costs, space-borne instruments should be considered only for their exclusive capabilities in helio-and asteroseismology. Space-borne high resolution spectrometers and photometers operate free of atmospheric pertubations, can be put on special orbits offering continuous (uninterrupted) observations and therefore offer the best opportunity for high signal-over-noise ratio. The recent data obtained on board the Phobos-2 mission clearly evidences this fact. The ESA-NASA SOHO observatory will be the first mission of its kind carrying a comprehensive set of instruments to analyse the gravity and acoustic modes of solar oscillations over an uninterrupted period of at least 2 years. Projects also exist to observe oscillations of the solar diameter. Long term observation of the solar constant may provide a clue to the understanding of the origins of the solar cycle. Simultaneous out of eliptic measurements may nicely complement our data set and offer unambiguous views on the asymmetries of the solar interior. Space observations are probably the only means to get access to the deep solar interior through the detections of g modes. They offer the only prospect in the exploitation of asteroseismology over a larger number of stars.

scholarly journals The Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database: A long-term database for climate studies

2016 ◽  
Author(s):  
Sean M. Davis ◽  
Karen H. Rosenlof ◽  
Birgit Hassler ◽  
Dale F. Hurst ◽  
William G. Read ◽  
...  
Keyword(s):  
Water Vapor ◽  
Data Set ◽  
Future Studies ◽  
Source Data ◽  
Reference Satellite ◽  
Data Record ◽  
Reference Measurements ◽  
Climate Studies ◽  
Term Data

Abstract. In this paper, we describe the construction of the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) database, which includes vertically resolved ozone and water vapor data from limb profiling satellite instruments operating since the 1980’s. SWOOSH includes both individual satellite source data as well as a merged data product. A key aspect of the merged product is that the source records are homogenized to account for inter-satellite biases and to minimize artificial jumps in the record. We describe the SWOOSH homogenization process, which involves adjusting the satellite data records to a “reference” satellite using coincident observations during time periods of instrument overlap. The reference satellite is chosen based on the best agreement with independent balloon-based sounding measurements, with the goal of producing a long-term data record that is both homogeneous and accurate. This paper details the choice of reference measurements, homogenization, and gridding process involved in the construction of the combined SWOOSH product, and also presents the ancillary information stored in SWOOSH that can be used in future studies of water vapor and ozone variability. Furthermore, a discussion of uncertainties in the combined SWOOSH record is presented, and examples of the SWOOSH record are provided to illustrate its use for studies of ozone and water vapor variability on interannual to decadal time scales. The version 2.5 SWOOSH data are publicly available at https://data.noaa.gov/dataset/stratospheric-water-and-ozone-satellite-homogenized-swoosh-data-set.

scholarly journals Workshop on Overcoming Measurement Barriers to Internet Research (WOMBIR 2021) final report

2021 ◽  
Vol 51 (3) ◽  
pp. 33-40
Author(s):  
KC Claffy ◽  
David Clark ◽  
John Heidemann ◽  
Fabian Bustamante ◽  
Mattijs Jonker ◽  
...  
Keyword(s):  
Critical Infrastructure ◽  
Measurement Data ◽  
Internet Research ◽  
Final Report ◽  
Data Sets ◽  
Data Set ◽  
Research Areas ◽  
Mobile Networking ◽  
Network Properties

In January and April 2021 we held the Workshop on Overcoming Measurement Barriers to Internet Research (WOMBIR) with the goal of understanding challenges in network and security data set collection and sharing. Most workshop attendees provided white papers describing their perspectives, and many participated in short-talks and discussion in two virtual workshops over five days. That discussion produced consensus around several points. First, many aspects of the Internet are characterized by decreasing visibility of important network properties, which is in tension with the Internet's role as critical infrastructure. We discussed three specific research areas that illustrate this tension: security, Internet access; and mobile networking. We discussed visibility challenges at all layers of the networking stack, and the challenge of gathering data and validating inferences. Important data sets require longitudinal (long-term, ongoing) data collection and sharing, support for which is more challenging for Internet research than other fields. We discussed why a combination of technical and policy methods are necessary to safeguard privacy when using or sharing measurement data. Workshop participant proposed several opportunities to accelerate progress, some of which require coordination across government, industry, and academia.

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