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1.
We develop a semiempirical spectral model of penetrating irradiance taking into account the biooptical characteristics of
the Black Sea. The evaluation of the contributions of the principal optically active components to the total absorption of
light in the sea shows that, in the short-wave range (400–500 nm), light is mainly absorbed by the dissolved organic matter
(41–77%). The contribution of phytoplankton to the total absorption attains its maximum values (26–37%) in the abyssal part
of the sea in the period of spring blooming of diatoms. In the coastal waters, the absorption of light by suspended nonalgae
particles in summer is almost twice as intense (20–30%) as in the open sea (8–13%). The analysis of the sensitivity of our
model shows that the absorption of light by dissolved organic matter is more significant for the estimation of the photosynthetically
active radiation in the Black Sea than the concentration of pigments and backscattering of light by suspended particles. The
comparison of the results of model computations with the data of measurements of the underwater irradiance reveals high accuracy
of the proposed model. 相似文献
2.
M. V. Makarova A. V. Poberovskii K. N. Visheratin A. V. Polyakov 《Izvestiya Atmospheric and Oceanic Physics》2009,45(6):723-730
The results of measuring the methane content in the entire atmospheric thickness over the St. Petersburg region are given
for 1991–2007. It is shown that, within this period, the mean annual cycle of the total methane content is characterized by
its maximum values in December–January and its minimum values in June–August when the annual-cycle amplitude amounts to ∼3.6%.
In this case, the annual variations in the total methane content may differ significantly from the mean annual cycle obtained
in some years. A statistically significant linear trend of the total CH4 content has not been revealed for 1991–2007. The obtained values of the linear-trend index have opposite signs in the winter
and summer months (positive for January 0.6 ± 0.2%/year and February 0.4 ± 0.2%/year and negative for July 0.3 ± 0.2%/year
and August 0.2 ± 0.1%/year). This fact suggests the tendency for an increase in the amplitude of the annual cycle of the total
CH4 content. The results of a spectral analysis of a series of data on the total CH4 content show that, for 1991–2007, the following harmonics are pronounced with a confidence of 95%: 12 months (annual harmonic),
32 months (quasi-biennial oscillations), and 55 months (4.5 years), which are also pronounced in the series of meteorological
parameters and total ozone content. 相似文献
3.
Hiroshi Murakami Kosei Sasaoka Kohtaro Hosoda Hajime Fukushima Mitsuhiro Toratani Robert Frouin B. Greg Mitchell Mati Kahru Pierre-Yves Deschamps Dennis Clark Stephanie Flora Motoaki Kishino Sei-Ichi Saitoh Ichio Asanuma Akihiko Tanaka Hiroaki Sasaki Katsumi Yokouchi Yoko Kiyomoto Hiroaki Saito Cécile Dupouy Absornsuda Siripong Satsuki Matsumura Joji Ishizaka 《Journal of Oceanography》2006,62(3):373-393
The Global Imager (GLI) aboard the Advanced Earth Observing Satellite-II (ADEOS-II) made global observations from 2 April
2003 to 24 October 2003. In cooperation with several institutes and scientists, we obtained quality controlled match-ups between
GLI products and in-situ data, 116 for chlorophyll-a concentration (CHLA), 249 for normalized water-leaving radiance (nLw) at 443 nm, and 201 for
aerosol optical thickness at 865 nm (Tau_865) and Angstrom exponent between 520 and 865 nm (Angstrom). We evaluated the GLI
ocean color products and investigated the causes of errors using the match-ups. The median absolute percentage differences
(MedPD) between GLI and in-situ data were 14.1–35.7% for nLws at 380–565 nm, 52.5–74.8% nLws at 625–680 nm, 47.6% for Tau_865, 46.2% for Angstrom, and 46.6%
for CHLA, values that are comparable to the ocean-color products of other sensors. We found that some errors in GLI products
are correlated with observational conditions; nLw values were underestimated when nLw at 680 nm was high, CHLA was underestimated
in absorptive aerosol conditions, and Tau_865 was overestimated in sunglint regions. The error correlations indicate that
we need to improve the retrievals of the optical properties of absorptive aerosols and seawater and sea surface reflection
for further applications, including coastal monitoring and the combined use of products from multiple sensors. 相似文献
4.
The shortwave radiative forcings of smoke aerosol in the cloudless atmosphere during the summer fires of 2010 in European
Russia were quantitatively estimated for the land surface and the atmospheric upper boundary from measurement data obtained
at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics (OIAP ZSS), Russian Academy of Sciences.
Variations in the temperature of the surface air layer due to the smoke-induced attenuation of incoming solar radiation were
estimated. The most intensive smoke generation in the atmosphere was observed on August 7–9, 2010, when the maximum aerosol
optical thickness amounted to more than 4.0 at a wavelength of 550 nm. In this case, the albedo of single aerosol scattering
amounted to ∼0.95–0.96 and the asymmetry factor amounted to ∼0.69–0.70. The maximum shortwave radiative forcing of aerosol
amounted to about −360 W/m2 for the land surface and almost −150 W/m2 for the atmospheric upper boundary. During the period of intensive smoke generation, the cooling of the atmospheric surface
layer over daylight hours (12 h) amounted, on average, to ∼6°C. The power character of the dependence of the shortwave radiative
forcing of aerosol for the land surface on aerosol optical thickness up to its values exceeding 4.0, which was revealed earlier
on the basis of data on aerosol optical thickness (up to 1.5) obtained at the OIAP ZSS during the summer forest and peatbog
fires of 2002 in the region of Moscow, was supported. 相似文献
5.
Robert Frouin Pierre-Yves Deschamps Lydwine Gross-Colzy Hiroshi Murakami Takashi Y. Nakajima 《Journal of Oceanography》2006,62(3):331-337
Top-of-atmosphere reflectance measured above the ocean in the visible and near infrared, after correction for molecular scattering,
may be linearly combined to retrieve surface chlorophyll-a abundance directly, without explicit correction for aerosol scattering
and absorption. The coefficients of the linear combination minimize the perturbing effects, which are modeled by a polynomial,
and they do not depend on geometry. The technique has been developed for Global Imager (GLI) spectral bands centered at 443,
565, 667, and 866 nm, but it is applicable to other sets of spectral bands. Theoretical performance is evaluated from radiation-transfer
simulations for a wide range of geophysical and angular conditions. Using a polynomial with exponents of −2, −1, and 0 to
determine the coefficients, the residual influence of the atmosphere on the linear combination is within ±0.001 in most cases,
allowing chlorophyll-a abundance to be retrieved with a root-mean-squared (RMS) error of 8.4% in the range 0.03–3 mgm−3. Application of the method to simulated GLI imagery shows that estimated and actual chlorophyll-a abundance are in agreement,
with an average RMS difference of 32.1% and an average bias of −2.2% (slightly lower estimated values). The advantage of the
method resides in its simplicity, flexibility, and rapidity of execution. Knowledge of aerosol amount and type is avoided.
There is no need for look-up tables of aerosol optical properties. Accuracy is adequate, but depends on the polynomial representation
of the perturbing effects and on the bio-optical model selected to relate the linear combination to chlorophyll-a abundance.
The sensitivity of the linear combination to chlorophyll-a abundance can be optimized, and the method can be extended to the
retrieval of other bio-optical variables. 相似文献
6.
In this paper, we demonstrate the effectiveness of steerable filters as a method of delineating the boundaries of subsurface geological structures. Steerable filters, generally used for edge detection on 2-D images, have the properties of band pass filters with certain directions and are applied to many image processing problems. We first tested the method on synthetic data and then applied it to the aeromagnetic data of İskenderun Basin and adjacent areas.İskenderun Basin is located in the Northeastern Mediterranean where African–Arabian and Anatolian plates are actively interacting. The basin fill records a complex tectonic evolution since the Early Miocene, involving ophiolite emplacement, diachronous collision of Eurasian and Arabian plates and subsequent tectonic escape related structures and associated basin formation. Geophysical investigations of the tectonic framework of İskenderun Basin of Turkey provide important insights on the regional tectonics of the Eastern Mediterranean and Middle East. In this study we show geological structures, which are responsible for the magnetic anomalies in İskenderun Basin and enlighten the structural setting of the Northeastern Mediterranean triple junction using steerable filters. We obtained a magnetic anomaly map of the region from the General Directorate of Mineral Research and Exploration as raw data and then evaluated this by steerable filters. We determined the magnetic anomaly boundaries for İskenderun Basin by using various types of steerable filters and correlated these to drilling data and seismic profiles from the Turkish Petroleum Corporation. The result of the steerable filter analysis was a clarified aeromagnetic anomaly map of İskenderun Basin. The tectonic structure of İskenderun Basin is divided into regions by an N–S trending oblique-slip fault defined by the steerable filter outputs. We propose a new tectonic structure model of İskenderun Basin and modify the direction of the East Anatolian Fault Zone. In our model, East Anatolian Fault Zone cross-cuts the basin as a narrow fault zone and continues towards the Cyprus arc. 相似文献
7.
The temporal variability of the chemical composition of surface aerosol with particle diameters of 0.7–2 μm is analyzed. This
analysis is based on the results of measurements of infrared transmission spectra of aerosol samples collected with the use
of a cascade impactor at the Zvenigorod Scientific Station of the Institute of Atmospheric Physics (IAP) in 1999–2005. Seasonal
features of the aerosol chemical composition and its dependence on the particle size are revealed. The interdiurnal variability
of the aerosol composition depends on the season, and it manifests itself more strongly in winter and spring. Air-mass changes
lead to changes in the relation of sulfates and nitrates in the micron fraction of aerosol. The enrichment of samples in nitrates
is especially characteristic of the winter and spring seasons. Compounds containing the NO2 group are often met in the samples of aerosol with particle sizes of 0.7–1.3 μm during the cold time of the year. The estimates
of the optical thickness of micron aerosol in the sulfate absorption band are obtained, and optical-thickness variations of
some scales are detected. The quantitative characteristics of statistical relations between different chemical components
of aerosol inside individual fractions and between chemical components of the micron and submicron fractions are obtained
and analyzed. 相似文献
8.
Hajime Fukushima Akiko Higurashi Yasushi Mitomi Teruyuki Nakajima Toshimitsu Noguchi Toshio Tanaka Mitsuhiro Toratani 《Journal of Oceanography》1998,54(5):417-430
This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic
structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model”
introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the observations at 670
and 865 nm bands, the algorithm selects a pair of aerosol models that account best for the observed spectral reflectances,
and synthesizes the aerosol reflectance used for the atmospheric correction. Two different schemes for determining the value
of the parameter for the aerosol model selection are presented and their anticipated estimation error is analyzed in terms
of retrieved water reflectance at 443 nm. The results of our numerical simulation show that the standard deviation of the
estimation error of the “weighted average” scheme is mostly within the permissible level of ±0.002, reducing the error by
18% on average compared to the “simple average” scheme. The paper further discusses the expected error under the old CZCS-type
atmospheric correction, which assumes constant aerosol optical properties throughout the given image. Although our algorithm
has a better performance than the CZCS algorithm, further analysis shows that the error induced by the assumption taken in
the algorithm that the water-leaving radiance at 670 nm band is negligibly small may be large in high pigment concentration
waters, indicating the necessity for future improvements. 相似文献
9.
We present the results of analysis of the variability of hydrometeorological and hydrophysical fields near the west and southwest
coasts of Crimea on scales varying from 1–100 days to 1–11 yr according to the data of long-term routine (4–8 h) observations
performed at the coastal marine hydrometeorological stations. New methods of filtration and spectral analysis are used to
reveal the characteristic time scales of variability including the quasiperiodic and periodic components and study the physical
processes responsible for the indicated variability. Special attention is given to the analysis of correlation between the
periodic variability of the fields in the atmosphere and in the coastal zone on different time scales.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 22–36, January–February, 2006. 相似文献
10.
A. P. Ivanov I. L. Katsev A. S. Prikhach E. P. Zege 《Izvestiya Atmospheric and Oceanic Physics》2014,50(2):188-195
Methods and algorithms for the retrieval of optical characteristics of the aerosol atmosphere and underlying surface by data from a multispectral satellite sensor (MSSS) are described. A procedure for the joint processing of MSSS and multizonal imaging system (MZIS) data is proposed and described with the aim of retrieving the albedo of the Earth’s surface with a high spatial resolution. In this case the spectral optical characteristics of the aerosol atmosphere are retrieved by MSSS data in the visible range of 400–700 nm. According to these results, transmission functions of the atmosphere in MZIS spectral channels are calculated and an atmospheric correction of MZIS data is performed. The accuracy of determining the albedo of the underlying surface in spectral channels of MZIS with high-spatial-resolution is estimated. 相似文献
11.
V. I. Man'kovsky 《Physical Oceanography》2001,11(3):299-304
On the basis of the data of optical investigations performed in the Black Sea, we develop a method for the evaluation of the
spectral values of underwater quantum irradiance within the band of photosynthetically active radiation according to the depth
of visibility of a Secchi disk and the intensity of illumination of the sea in luxes. The method is based on the use of the
correlations between the following optical parameters: of the vertical daylight attenuation factor α with the depth of visibility
of a Secchi disk and of the spectral values of α(λ) within the band of photosynthetically active radiation with α(λmin) for sea waters. This method is applicable in the winter-spring period when the seasonal thermocline is absent, the upper
layers of the sea are mixed, and the vertical distribution of α is uniform.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
12.
Hiroaki Sasaki Akihiko Tanaka Mitsunori Iwataki Yasuharu Touke Eko Siswanto Chun Knee Tan Joji Ishizaka 《Journal of Oceanography》2008,64(4):511-523
Remote sensing reflectance [R
rs(λ)] and absorption coefficients of red tides were measured in Isahaya Bay, southwestern Japan, to investigate differences in
the optical properties of red tide and non-red tide waters. We defined colored areas of the sea surface, visualized from shipboard,
as “red tides”. Peaks of the R
rs(λ) spectra of non-red tide waters were at 565 nm, while those of red tides shifted to longer wavelengths (589 nm). The spectral
shape of R
rs(λ) was close to that of the reciprocal of the total absorption coefficient [1/a(λ)], implying that the R
rs(λ) peak is determined by absorption. Absorption coefficients of phytoplankton [a
ph(λ)], non-pigment particles and colored dissolved organic matter increased with increasing chlorophyll a concentration (Chl a), and those coefficients were correlated with Chl a for both red tide and non-red tide waters. Using these relationships between absorption coefficients and Chl a, variation in the spectrum of 1/a(λ) as a function of Chl a was calculated. The peak of 1/a(λ) shifted to longer wavelengths with increasing Chl a. Furthermore, the relative contribution of a
ph(λ) to the total absorption in red tide water was significantly higher than in non-red tide water in the wavelength range 550–600
nm, including the peak. Our results show that the variation of a
ph(λ) with Chl a dominates the behavior of the R
rs(λ) peak, and utilization of R
rs(λ) peaks at 589 and 565 nm may be useful to discriminate between red tide and non-red tide waters by remote sensing. 相似文献
13.
The long-wave outgoing radiation, effective cloudiness equal to the product of the total cloud amount by their optical density,
and the sea-surface temperature determined from the satellites are used to determine the annual course of the components of
external heat balance on the sea surface whose climatic anomalies, parallel with the meridional heat and water transfer in
the ocean-atmosphere system, specify the intraannual and interannual large-scale variations of weather in different regions
of the Earth. The development of these studies is connected with the progress of satellite hydrophysics because the data obtained
from the space become sufficiently exact, regular, and global. The increase in the existing data array on the external heat
balance of the oceans from ∼15–20 to 100 yr and more would promote the solution of the problem of oscillations of Earth's
climate. We present examples of coordinated numerical analysis of the heat balance of the upper (0–100 m ) layer of the Black
Sea performed on the basis of the shipborne and satellite data.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 59–75, November–December, 2007. 相似文献
14.
N. A. Timofeev 《Physical Oceanography》2011,20(6):451-469
The temperature of waters in the upper layer of the ocean and effective cloudiness (cloudiness with simultaneous indication
of its amount and optical density) are important characteristics of the natural environments. They determine the greenhouse
effects and the energy of the ocean and atmosphere, and regulate climate. The satellite data on these characteristics enable
one to reconstruct all components of the radiation, heat, and water budgets in the ocean–atmosphere system and study their
intra- and interannual variations. We describe the procedures of evaluation of the effective cloudiness according to the sea-surface
temperature and the radiation temperature in the spectral range 10.3–11.3 μm. The development of these investigations is connected
with the advances in satellite hydrophysics: the satellite data become more and more accurate, regular, and global. 相似文献
15.
The first empirical orthogonal functions (EOF1s) of surface-air temperature fluctuations for Russia and its neighboring states
within the period 1950–2005 are analyzed. The spatial distribution of the EOF1, the first principal components (PC1s) of the
observed air temperature (averaged over the summer, July, December–March, and individual winter months), and their time variations
(including trend parameters, some spectral characteristics, and the quantitative indices of relation to circulation indices
(on the basis of multiple step-by-step regression)) are considered. Significant seasonal differences have been revealed: the
winter air-temperature fluctuations are characterized by a higher (when compared to summer) spatial coherence, especially
in the latitudinal direction. The EOF1 of the winter air temperature (averaged over December–March) describes its fluctuations
for almost all of Russia; in this case, no less than 70% of the PC1 variability is due to variations in several circulation
indices; the main contribution (60%) is made by both the North Atlantic Oscillation (NAO) and Scandinavian (SCAND) indices.
On the whole, over the periods 1951–2005 and 1971–2005, the NAO contribution exceeds the SCAND contribution to the winter
temperature variability; the NAO is associated with a more rapid increase in air temperature in 1968–1997 and with the 1971–2005
trend. In 1951–1970 the main contribution to air temperature fluctuations was made by SCAND; the SCAND contribution exceeds
the NAO contribution in the periods 1951–2005 and 1971–2005. The 1971–2005 and 1968–1997 temperature trends are completely
described by variations in the NAO (70%) and SCAND (30%) indices for January and February. 相似文献
16.
17.
V. V. Zuev S. L. Bondarenko N. E. Zueva 《Izvestiya Atmospheric and Oceanic Physics》2011,47(9):1032-1038
The response of the total ozone (TO) at subarctic latitudes to volcanic eruptions, products of which were injected into the
stratosphere, is analyzed. It is established that the behavior of the series of average annual TO values according to the
TOMS, SCIAMACHY, and GOME space equipment data averaged for 55°–65° N latitudes agrees with the activity of explosive volcanic
eruptions. The series of the TO satellite monitoring instrumental data are extended by 200 years into the past using a reconstruction
from the dendro-chronologic data. An analysis of the series of TO reconstructed values indicates that volcanogenic perturbations
of the subarctic ozonosphere initiate long-term negative TO deviations. In this case, the TO negative deviation depth depends
on the frequency of the ozonosphere volcanogenic perturbations and the phase of quasiperiodic oscillation cycles rather than
on the strength of a single volcanic explosion. 相似文献
18.
Yudi Adityawarman Arata Kaneko Koji Nakano Naokazu Taniguchi Katsuaki Komai Xinyu Guo Noriaki Gohda 《Journal of Oceanography》2011,67(2):173-182
A 30 km-range reciprocal sound transmission experiment was carried out on the line connecting Honshu and Shikoku (the first
and fourth biggest main Japanese islands, respectively) in the central part (Aki-nada) of the Seto Inland Sea, Japan, during
March–May 2010 to measure the mean current and temperature variations over the sea. The range-averaged current along the sound
transmission line was estimated to have a mean and standard deviation of (3.8–4.4) ± (1.7–1.8) cm/s after converting the travel
time difference data into currents, including a fortnightly tidal variation in the range of ±30 cm/s. The positive mean current
implies slow water movement from the west to east through Aki-nada. The range-averaged speed of sound was estimated by converting
from the mean travel time or one-way travel time into the speed of sound, and further converted into temperature for fixed
values of salinity and depth, according to the standard speed of sound formula. Besides the precise measurement (to an accuracy
of 0.01°C) of semidiurnal and diurnal tidal variations and seasonal warming, the temperature data showed periodic variations
with periods of 7.0 and 21.1 days that had never been observed in Aki-nada before. This study suggests that reciprocal sound
transmission is a powerful technique for the long-term accurate measurement of mean current and temperature variations in
coastal and inland seas. 相似文献
19.
The hydroacoustic method for the quantification of the gas flux from a submersed bubble plume 总被引:2,自引:0,他引:2
This article presents an inverse hydroacoustic method for the remote quantification of the total gas flux transported from
an underwater bubble plume. The method includes the surveying of the bubble plume by a vertically looking echo sounder and
the calculation of the flux using the spatial distribution of the ultrasound backscattering at a fixed depth. A simplified
parameterization containing only a few parameters is introduced to describe the empirical bubble size distribution. The linear
correlation between the backscattering cross section of the bubble stream and the vertical gas flux is found. The calculation
procedure takes into account the occurrence of a gas hydrate film at the bubble’s surface. The influence of different parameters
on the accuracy of the method is investigated. The resolution volume of the echo sounder corresponding to the fixed distance
is considered as a two-dimensional spatial window. The method was applied to quantify the total convective methane flux at
the Haakon-Mosby mud volcano (HMMV) depth 1280 m. The calculated values of the total flux near the bottom (100–400 t/year)
are in good agreement with the independently estimated flux for the single bubble jet observed from the ROV (70 t/year). These
calculations also show significant temporal variability of the flux at the HMMV. The total flux was found to vary by about
a factor of 2–3 within time scales of days. 相似文献
20.
N. F. Elansky 《Izvestiya Atmospheric and Oceanic Physics》2012,48(3):281-298
This review contains the most important results obtained in studies of atmospheric ozone in 2007–2010. It is part of the Russian national report on meteorology and atmospheric sciences that was prepared for the International Association of Meteorology and Atmospheric Sciences (IAMAS). This report was considered and approved at the XXV General Assembly of the International Union of Geodesy and Geophysics (IUGG). The list of publications by Russian scientists for 2007–2010 is appended to this review. Not all of these publications are cited here, but all of them are devoted to this topic and contain results that may be of interest to specialists in the fields of meteorology and atmospheric sciences. 相似文献