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1.
Int J Mol Sci ; 25(7)2024 Apr 05.
Article in English | MEDLINE | ID: mdl-38612852

ABSTRACT

Salinity is an environmental stress that severely impacts rice grain yield and quality. However, limited information is available on the molecular mechanism by which salinity reduces grain quality. In this study, we investigated the milling, appearance, eating and cooking, and nutritional quality among three japonica rice cultivars grown either under moderate salinity with an electrical conductivity of 4 dS/m or under non-saline conditions in a paddy field in Dongying, Shandong, China. Moderate salinity affected rice appearance quality predominantly by increasing chalkiness rate and chalkiness degree and affected rice eating and cooking and nutritional quality predominantly by decreasing amylose content and increasing protein content. We compared the expression levels of genes determining grain chalkiness, amylose content, and protein content in developing seeds (0, 5, 10, 15, and 20 days after flowering) of plants grown under saline or non-saline conditions. The chalkiness-related gene Chalk5 was up-regulated and WHITE-CORE RATE 1 was repressed. The genes Nuclear factor Y and Wx, which determine amylose content, were downregulated, while protein-content-associated genes OsAAP6 and OsGluA2 were upregulated by salinity in the developing seeds. These findings suggest some target genes that may be utilized to improve the grain quality under salinity stress conditions via gene-pyramiding breeding approaches.


Subject(s)
Methamphetamine , Oryza , Oryza/genetics , Amylose , Plant Breeding , Salt Stress , Seeds/genetics , Calcium Carbonate , Edible Grain/genetics
2.
J Environ Sci (China) ; 114: 354-364, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35459498

ABSTRACT

To investigate particle characteristics and find an effective measure to control severe particle pollution, year-round observation of size-segregated inorganic aerosols was conducted in Beijing from January to December, 2016. The sampled atmospheric particles all presented bimodal size distribution at four pollution levels (clear, slight pollution, moderate pollution and severe pollution), and peak values appeared at the size range of 0.7-2.1 µm and >9.0 µm, respectively. As dominant particle compositions, NO3-, SO42-, and NH4+ in four pollution levels all showed significant peaks in fine mode, especially at the size range of 1.1-2.1 µm. Secondary inorganic aerosols accounted for about 67.6% (36.3% (secondary sulfates) + 31.3% (secondary nitrates)) of the total sources of fine particles in urban Beijing. Severe pollution of fine particles was mainly caused by the air masses transported from nearby western and southern areas, which are industrial and densely populated region, respectively. Sensitivity tests further revealed that the control measures focusing on ammonium emission reduction was the most effective for particle pollution mitigation, and fine particles all showed nonlinear responses after reducing ammonium, nitrate, and sulfate concentrations, with the fitting curves of y = -120.8x - 306.1x2 + 290.2x3, y = -43.5x - 67.8x2, and y = -25.8x - 110.4x2 + 7.6x3, respectively (y and x present fine particle mass variation (µg/m3) and concentration reduction ratio (CRR)/100 (dimensionless)). Overall, our study presents useful information for understanding the characteristics of atmospheric inorganic aerosols in urban Beijing, as well as offers policy makers with effective measure for mitigating particle pollution.


Subject(s)
Air Pollutants , Ammonium Compounds , Aerosols/analysis , Air Pollutants/analysis , Ammonium Compounds/analysis , Beijing , China , Environmental Monitoring , Nitrates/analysis , Particle Size , Particulate Matter/analysis , Seasons , Sulfates/analysis
3.
Plant Physiol Biochem ; 152: 138-146, 2020 May 06.
Article in English | MEDLINE | ID: mdl-32416343

ABSTRACT

Glucosyltransferases-like GTPase activators and Myotubularin (GRAM) domain-containing proteins are important for plant development and responses to biotic stresses. However, the effects of GRAM proteins on abiotic stress responses remain unclear. In this study, we identified a novel GRAM protein-encoding gene, OsABAR1, and characterized its regulatory functions related to rice drought and salt tolerance. The OsABAR1 protein was localized in the cytoplasm and nucleus. Among all examined organs, the OsABAR1 transcript level was highest in the roots. Moreover, OsABAR1 expression was up-regulated by drought and salinity stresses. The OsABAR1-overexpressing (OsABAR1-OX) lines exhibited enhanced tolerance to drought and salinity, whereas the knock-out lines (Osabar1) had the opposite phenotypes. We further analyzed the involvement of OsABAR1 in the abscisic acid (ABA) signaling pathway. The OsABAR1 expression level was up-regulated by ABA. In turn, OsABAR1 regulated the expression of ABA metabolic genes and responsive genes. Furthermore, OsABAR1-OX seedlings were hypersensitive to exogenous ABA, whereas Osabar1 seedlings were hyposensitive. These results imply that OsABAR1 is a positive regulator of the ABA pathway and confirm that OsABAR1 improves rice drought and salt tolerance via an ABA-dependent pathway. This study is the first to clarify the regulatory roles of GRAM proteins in rice responses to abiotic stresses.

5.
Sensors (Basel) ; 19(9)2019 May 10.
Article in English | MEDLINE | ID: mdl-31083293

ABSTRACT

Sea surface emissivity (SSE) is a key variable in the estimation of sea surface temperature and the sea surface radiation budget. A physical base SSE model with adequate accuracy and acceptable computational efficiency is highly desired. This paper develops a Monte Carlo ray-tracing model to compute the SSE of a wind-roughened sea surface. The adoption of a two-dimensional continuous surface model and averaging the two polarization components in advance before ray-tracing gives the model acceptable computational efficiency. The developed model can output the contributions of direct emission and the reflected component to the effective emissivity. The contribution of the reflected component to the effective emissivity reaches 0.035 at an 80° emission angle for a wind speed larger than 10 m/s. The emissivity spectra and channel emissivities collected from two field campaigns and one set of outdoor measurements are used to validate the developed model. Statistical results indicate that the absolute value of bias or difference is less than 0.5% when the view angle is less than 65°, which means the retrieval accuracy of sea surface temperature (SST) is guaranteed from the view of SSE. When the view angle increases, the accuracy of the developed model degraded, especially at the view angle of 85°. Without considering this view angle, the absolute value of bias or difference is less than 0.016, and the root mean square difference (RMSD) is less than 0.018.

6.
J Crit Care ; 48: 314-320, 2018 12.
Article in English | MEDLINE | ID: mdl-30278407

ABSTRACT

PURPOSES: The present study examined the value of P(v-a)CO2/C(a-v)O2 compared with ScvO2 as a target for clinical resuscitation of severe sepsis/septic shock. MATERIALS AND METHODS: 228 patients were randomly divided into a P(v-a)CO2/C(a-v)O2-targeted and a ScvO2-targeted therapy group. The effects on hemodynamics, interventional intensity, and outcome were recorded and analyzed. RESULTS: The mean arterial pressure (MAP) of the P(v-a)CO2/C(a-v)O2-targeted therapy group was significantly higher at 3 h, 12 h, 24 h, and 3 days (P < .05). The P(v-a)CO2/C(a-v)O2 of the ScvO2-targeted therapy group was significantly higher at each time point after resuscitation (P < .05). However, the CVP, lactate, urine output, ScvO2, and P(v-a)CO2 were not significantly improved. The P(v-a)CO2/C(a-v)O2-targeted therapy group used a smaller fluid volume and required fewer red blood cell transfusions and vasoactive drugs, but these results were also not significant. There were no differences between 28-day and 60-day mortality, APACHEII and SOFA scores, ICU length of stay, residence length of stay, number of days free of vasoactive drugs, or number of ventilator-free days. Post hoc tests revealed no significant differences between these two groups in 28-day survival. CONCLUSION: P(v-a)CO2/C(a-v)O2-directed resuscitation did not improve prognosis compared with ScvO2 in severe sepsis and septic shock. ClinicalTrials.gov Identifier NCT01877798.


Subject(s)
Carbon Dioxide/administration & dosage , Oxygen/administration & dosage , Sepsis/therapy , Arterial Pressure , Blood Gas Analysis , Carbon Dioxide/blood , China , Female , Humans , Lactic Acid/blood , Male , Middle Aged , Oxygen/blood , Oxygen Inhalation Therapy , Prognosis , Prospective Studies , Resuscitation/methods , Sepsis/blood , Sepsis/mortality , Shock, Septic/blood , Shock, Septic/mortality , Shock, Septic/therapy , Treatment Outcome
7.
J Environ Sci (China) ; 71: 283-291, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30195686

ABSTRACT

Through field sampling of atmospheric dustfall in regions of Zhuzhou City, China for a period of one year, the deposition fluxes of atmospheric dustfall and five heavy metals contained inside, including Cr, As, Cd, Hg and Pb, were analyzed. Meanwhile the enrichment factor and index methods were used to analyze the pollution characteristics of heavy metals of atmospheric dustfall in Zhuzhou. The annual deposition flux of atmospheric dustfall in Zhuzhou was 50.79 g/(m2·year), while the annual deposition fluxes of Cr, As, Cd, Hg and Pb were 9.80, 59.69, 140.09, 0.87 and 1074.91 mg/(m2·year), respectively. The pollution level of atmospheric dustfall in Zhuzhou was relatively lower compared with most other cities in China, but the deposition fluxes of As, Cd, Hg and Pb in atmospheric dustfall in Zhuzhou were much higher than that in most cities and regions around the world. Cd is the typical heavy metal element in atmospheric dustfall in Zhuzhou, and both the enrichment factor and pollution index of Cd were the highest. Cd, Hg, Pb and As in atmospheric dustfall were mainly from human activities. According to the single-factor index, Nemerow index and pollution load index analyses, the atmospheric dustfall in Zhuzhou could easily cause severe heavy metal pollution to urban soil, and the most polluting element was Cd, followed by Pb, As and Hg. Only the pollution level of Cr lay in the safety region and mainly originated from natural sources.


Subject(s)
Air Pollutants/analysis , Dust/analysis , Environmental Monitoring , Metallurgy , Metals, Heavy/analysis , Soil Pollutants/analysis , China , Soil
8.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 29(11): 1004-1009, 2017 Nov.
Article in Chinese | MEDLINE | ID: mdl-29151416

ABSTRACT

OBJECTIVE: To evaluate the efficacy and safety of short-term deep sedation strategy in patients with spontaneous intracerebral hemorrhage (ICH) after surgery. METHODS: A perspective, randomized, parallel-group study was conducted. Adult patients with spontaneous ICH and undergoing craniotomy admitted to Daxing Teaching Hospital of Capital Medical University from December 2015 to November 2016 were enrolled. The patients who received surgery were randomly divided into a short-term deep sedation and a slight and middle sedation group. Sufentanil was used as an analgesic drug in all patients and midazolam was used as a sedative after the operation. The patients in the slight and middle sedation group received midazolam 0.05-0.10 mg/kg with a goal of mild sedation [Richmond agitation and sedation scale (RASS) score of -2-1]. The patients in the short-term deep sedation group received midazolam 0.1-0.2 mg/kg with a goal of deep sedation (RASS score of -4 to -3) and a duration of no more than 12 hours. Postoperative sedation, blood pressure changes, laboratory indexes, residual hematoma and clinical outcomes were recorded in two groups. RESULTS: During the study, a total of 183 patients with spontaneous ICH were collected, excluding who was older than 65 years, with shock, and with preoperative Glasgow coma score (GCS) of 3. 106 patients were enrolled in this study, and 53 patients were assigned to the short-term deep sedation group and slight and middle sedation group, respectively. In the slight and middle sedation group, 4 patients received reoperation because of repeated hemorrhage and no patient operated repeatedly in the short-term deep sedation group, and there was a significant difference between the two groups (χ 2 = 4.000, P = 0.045). The number of patients undergoing tracheotomy in the short-term deep sedation group was significantly lower than that in the slight and middle sedation group (9 cases vs. 21 cases, P < 0.05). RASS score within 12 hours after operation of the patients in the short-term deep sedation group was lower than that in slight and middle sedation group [-4 (-4, -2) vs. -2 (-3, -1) at 4 hours, -4 (-4, -2) vs. -1 (-2, 0) at 8 hours, -3 (-4, -2) vs. 0 (-2, 1) at 12 hours, all P < 0.01], sudden restlessness was significantly reduced [times: 1 (0, 1) vs. 3 (2, 3), P < 0.01], and postoperative sedation duration was significantly prolonged [hours: 14.0 (8.3, 20.8) vs. 8.9 (3.4, 15.3), P < 0.05]. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) within 12 hours after operation in the short-term deep sedation group were significantly lower than those of the slight and middle sedation group [SBP (mmHg, 1 mmHg = 0.133 kPa): 136.8±30.5 vs. 149.1±33.5, DBP (mmHg): 85.0 (70.8, 102.3) vs. 89.0 (69.2, 116.7), both P < 0.05]. There were no significant differences in the arterial blood gas, routine blood test or coagulation function between the two groups at 24 hours after operation. The volume of residual hematoma at 2, 7 and 14 days after operation in the short-term deep sedation group was significantly decreased as compared with slight and middle sedation group (mL: 16.4±15.6 vs. 38.2±22.2 at 2 days, 9.6±8.7 vs. 20.6±18.6 at 7 days, 1.2±1.0 vs. 4.4±3.6 at 14 days, all P < 0.05), number of deaths in 3 months were significantly less (5 cases vs. 13 cases), and the patients with favorable prognosis were increased significantly (39 cases vs. 12 cases, both P < 0.05). CONCLUSIONS: The study results showed that short-term deep sedation strategy after surgery can reduce the incidence of adverse events and improve the prognosis of patients with spontaneous ICH, so it is safe and effective.


Subject(s)
Cerebral Hemorrhage , Deep Sedation , Humans , Hypnotics and Sedatives , Intensive Care Units , Midazolam , Respiration, Artificial
9.
Anesth Analg ; 125(1): 176-183, 2017 07.
Article in English | MEDLINE | ID: mdl-28027085

ABSTRACT

BACKGROUND: Excessively deep sedation is prevalent in mechanically ventilated patients and often considered suboptimal. We hypothesized that the bispectral index (BIS), a quantified electroencephalogram instrument, would accurately detect deep levels of sedation. METHODS: We prospectively enrolled 90 critically ill mechanically ventilated patients who were receiving sedation. The BIS was monitored for 24 hours and compared with the Richmond Agitation Sedation Scale (RASS) evaluated every 4 hours. Deep sedation was defined as a RASS of -3 to -5. Threshold values of baseline BIS (the lowest value before RASS assessment) and stimulated BIS (the highest value after standardized assessment) for detecting deep sedation were determined in a training set (45 patients, 262 RASS assessments). Diagnostic accuracy was then analyzed in a validation set (45 patients, 264 RASS assessments). RESULTS: Deep sedation was only prescribed in 6 (6.7%) patients, but 76 patients (84.4%) had at least 1 episode of deep sedation. Thresholds for detecting deep sedation of 50 for baseline and 80 for stimulated BIS were identified, with respective areas under the receiver-operating characteristic curve of 0.771 (95% confidence interval, 0.714-0.828) and 0.805 (0.752-0.857). The sensitivity and specificity of baseline BIS were 94.0% and 66.5% and of stimulated BIS were 91.0% and 66.5%. When baseline and stimulated BIS were combined, the sensitivity, specificity, and clinical utility index were 85.0% (76.1%-91.1%), 85.9% (79.5%-90.7%), and 66.9% (57.8%-76.0%), respectively. CONCLUSIONS: Combining baseline and stimulated BIS may help detect deep sedation in mechanically ventilated patients.


Subject(s)
Consciousness Monitors , Deep Sedation , Electroencephalography , Psychomotor Agitation/diagnosis , Respiration, Artificial , Adult , Aged , China , Consciousness , Critical Illness , Female , Humans , Hypnotics and Sedatives , Intensive Care Units , Male , Middle Aged , Monitoring, Physiologic , Prospective Studies , Reproducibility of Results , Sensitivity and Specificity
10.
Front Plant Sci ; 7: 1963, 2016.
Article in English | MEDLINE | ID: mdl-28083003

ABSTRACT

Cross talk between light signaling and cold signaling has been elucidated in the model plant Arabidopsis and tomato, but little is known about their relationship in rice. Here, we report that phytochrome B (phyB) mutants exhibit improved cold tolerance compared with wild type (WT) rice (Oryza sativa L. cv. Nipponbare). The phyB mutants had a lower electrolyte leakage index and malondialdehyde concentration than the WT, suggesting that they had greater cell membrane integrity and less lipid peroxidation. Real-time PCR analysis revealed that the expression levels of dehydration-responsive element binding protein 1 (OsDREB1) family genes, which functions in the cold stress response in rice, were increased in the phyB mutant under normal and cold stress conditions. PIFs are central players in phytochrome-mediated light signaling networks. To explore the relationship between rice PIFs and OsDREB1 gene expression, we produced overexpression lines of rice PIF genes. OsDREB1 family genes were up-regulated in OsPIL16-overexpression lines, which had improved cold tolerance relative to the WT. Chromatin immunoprecipitation (ChIP)-qPCR assay revealed that OsPIL16 can bind to the N-box region of OsDREB1B promoter. Expression pattern analyses revealed that OsPIL16 transcripts were induced by cold stress and was significantly higher in the phyB mutant than in the WT. Moreover, yeast two-hybrid assay showed that OsPIL16 can bind to rice PHYB. Based on these results, we propose that phyB deficiency positively regulates OsDREB1 expression through OsPIL16 to enhance cell membrane integrity and to reduce the malondialdehyde concentration, resulting in the improved cold tolerance of the phyB mutants.

11.
BMJ Open ; 5(4): e007542, 2015 Apr 21.
Article in English | MEDLINE | ID: mdl-25900467

ABSTRACT

INTRODUCTION: Emergence agitation after intracranial surgery is an important clinical issue during anaesthesia recovery. The aim of this multicentre cohort study is to investigate the incidence of emergence agitation, identify the risk factors and determine clinical outcomes in adult patients after intracranial surgery under general anaesthesia. Additionally, we will deliberately clarify the relationship between postoperative pneumocephalus and agitation. METHODS AND ANALYSIS: The present study is a prospective multicentre cohort study. Five intensive care units (ICUs) in China will participate in the study. Consecutive adult patients admitted to the ICUs after intracranial surgery will be enrolled. Sedation-Agitation Scale (SAS) or Richmond Agitation-Sedation Scale (RASS) will be used to evaluate the patients 12 h after the enrolment. Agitation is defined as an SAS score of 5-7, or an RASS score of +2 to +4. According to the maximal SAS and RASS score, patients will be divided into two cohorts: the agitation group and the non-agitation group. Factors potentially related to emergence agitation will be collected at study entry, during anaesthesia and operation, during postoperative care. Univariate analyses between the agitation and the non-agitation groups will be performed. The stepwise backward logistic regression will be carried out to identify the independent predictors of agitation. Patients will be followed up for 72 h after the operation. Accidental self-extubation of the endotracheal tube and removal of other catheters will be documented. The use of sedatives and analgesics will be collected. ETHICS AND DISSEMINATION: Ethics approval has been obtained from each of five participating hospitals. Study findings will be disseminated through peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: NCT02318199.


Subject(s)
Anesthesia Recovery Period , Brain/surgery , Neurosurgical Procedures , Postoperative Complications/etiology , Psychomotor Agitation/etiology , Adult , Aged , Aged, 80 and over , Anesthesia, General , Case-Control Studies , China , Clinical Protocols , Female , Humans , Incidence , Logistic Models , Male , Middle Aged , Pain, Postoperative/complications , Pain, Postoperative/diagnosis , Pneumocephalus/etiology , Postoperative Complications/epidemiology , Prospective Studies , Psychomotor Agitation/epidemiology , Risk Factors
12.
Opt Express ; 21(26): 32549-65, 2013 Dec 30.
Article in English | MEDLINE | ID: mdl-24514848

ABSTRACT

In this paper we propose a model to understand the polarization patterns of skylight when reflected off the surface of waves. The semi-empirical Rayleigh model is used to analyze the polarization of scattered skylight; the Harrison and Coombes model is used to analyze light radiance distribution; and the Cox-Munk model and Mueller matrix are used to analyze reflections from wave surface. First, we calculate the polarization patterns and intensity distribution of light reflected off wave surface. Then we investigate their relationship with incident radiation, solar zenith angle, wind speed and wind direction. Our results show that the polarization patterns of reflected skylight from waves and flat water are different, while skylight reflected on both kinds of water is generally highly polarized at the Brewster angle and the polarization direction is approximately parallel to the water's surface. The backward-reflecting Brewster zone has a relatively low reflectance and a high DOP in all observing directions. This can be used to optimally diminish the reflected skylight and avoid sunglint in ocean optics measurements.


Subject(s)
Environmental Monitoring/methods , Models, Chemical , Photometry/methods , Refractometry/methods , Seawater/analysis , Seawater/chemistry , Sunlight , Computer Simulation , Light , Scattering, Radiation , Surface Properties
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(12): 3416-21, 2012 Dec.
Article in Chinese | MEDLINE | ID: mdl-23427580

ABSTRACT

The present research describes the development of an improved cross-calibration method of on-orbit satellite sensor. The EO-1/Hyperion was taken as the referenced sensor and HJ-1A/HSI was taken as the uncalibrated sensor. The differences between the bands configurations were removed by the precise spectral response matching using the deconvolution method, which significantly reduced the radiometric calibration uncertainty of HSI sensor. The calibration coefficients of HSI for all 115 bands were acquired. The uncertainties of calibration coefficient from band 1 to band 60 stably lie in 5%-8%, and for all the other bands excerpt for the oxygen absorption which lies in at 760 nm and the water vapor absorption which lies in at 940 nm, the uncertainties of calibration coefficients are changed from 7% to 18%, which increased as the wavelength increased. Contrasted Compared with the traditional spectral matching method, the method proposed can improve the calibration accuracy by about 50%, which can meet the demand of the quantitive application for hyperspectral remote sensing data. It demonstrated the good precision and reliability of the method. It solved the spectral matching problem when the band configuration is big enough so that the cross calibration accuracy is too low and is difficult to apply in hyperspectral sensor cross-calibration, and provides a new method to frequently update the calibration coefficients for hyperspectral imager.

15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(7): 1853-7, 2010 Jul.
Article in Chinese | MEDLINE | ID: mdl-20827985

ABSTRACT

Eupatorium adenophorum Spreng. (EAS) is a toxic invasion plant and has caused significant economic and environmental impacts in China. The EAS has the characteristics of widely distributing and quickly spreading. The traditional detecting and supervising methods become invalid when applied for managing the spatial distribution of EAS. Based on the analyzing results of the spectrum features of EAS, the present paper tried to structure the identifying models by remote sensing. The main objective of this paper is to develop an available method for detecting and mapping the spatial distribution of EAS. The study shows that the spectrum of EAS has two reflecting peaks and one absorbing trough. The corresponding wavelengths of those peaks are 560, 730 and 674 nm, respectively. The absorption characteristics of EAS at 647 nm are that the absorbing depth is 0.504 3-1.910 3, the absorbing width is 13.778 9-17.251 8 nm and the area at the left absorption band is greater than the right, and the corresponding area ratio of left to right is 1.771 9-2.444 1. The white flowers of EAS make the reflectance higher at visible bands, and the first-order derivatives of EAS spectral show a wave peak at 420 nm. Compared with the spectral feature of other representative materials, the absorbing characteristics at 647 nm, such as absorption width and absorption depth, and the peak at 420 nm of derivatives spectral are special features of EAS spectral, which can be used as remotely sensed parameters for detecting and mapping the EAS at florescence.


Subject(s)
Ageratina , Introduced Species , Remote Sensing Technology , China , Spatial Analysis , Spectrum Analysis
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(5): 1347-51, 2010 May.
Article in Chinese | MEDLINE | ID: mdl-20672631

ABSTRACT

The errors of the territorial parameters retrieved from remote sensing are decided by the data error and the model error. The data error is not simply added to the total errors of retrieval results. It would be reformed by the quantitative inversion model, and then, combined with the model errors and melts into the totals errors. Accordingly, during the quantitative process, taking advantage of the highest correlation coefficient or the least root mean square error as assessment standard for describing the chlorophyll a concentration vs remote sensing parameters is not reasonable. Focusing on the above problem, the study pointed out that the reason why the result of the optimized cost function is contrary with the practical is that different model has different influence on data errors. Combined with the in situ measurements of Taihu Lake, in October, 2003, it is known that due to the error magnification phenomena (TM2/TM3 algorithm is 2.28 times more than TM2/TM1 algorithm), although the regression coefficient of TM2/TM3 algorithm is higher than TM2/TM1 algorithm, the quantitative errors of TM2/TM3 algorithm are 7.938 5 microg x L(-1) more than TM2/TM1 algorithm. Moreover, the retrieval results show that distribution pattern of the results of TM2/TM3 algorithm is completely opposite to the TM2/TM1 algorithm. According to the former research achievements, the results of TM2/TM1 algorithm would be more reasonable. In summary, only when that the factor of data error is added to the optimized cost function is taken as a constrain condition in search for the optimal solution of the quantitative models, would the retrieval results be more reliable.


Subject(s)
Chlorophyll/analysis , Environmental Monitoring , Lakes , Remote Sensing Technology , Algorithms , China , Chlorophyll A , Models, Theoretical
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(2): 470-5, 2010 Feb.
Article in Chinese | MEDLINE | ID: mdl-20384148

ABSTRACT

Based on aquatic optics Monte Carlo hyperspectral simulation, the interactions between spectral characteristics of chlorophyll a, total suspended matter (TSM) and colored dissolved organic matter (CDOM) were discussed. The result shows that the nonlinear and spectrally varying interactions between different water components are extremely highly asymmetric. The existing of chlorophyll a and CDOM has little effects on the characteristic wavebands selection and information retrieval of TSM, while the effects of TSM on chlorophyll a are obvious. With the stepwise additions of TSM, the response of chlorophyll a to its concentration becomes weak. When the concentration of TSM increases to a certain degree, the spectral response of chlorophyll a concentration will disappear. Even at the sensitivity waveband of chlorophyll a such as 670 nm, when the TSM is in high concentration, the spectral reflectance will not change with chlorophyll a concentration, which lead to difficulty to extract the chlorophyll a concentration in turbid water dominated by suspended matter. The existing of CDOM causes the blue and green band ratio algorithm to fail when the chlorophyll a is in middle to high concentration. The spectral effects on CDOM of the water body dominated by TSM are more obvious than that dominated by chlorophyll a. There are strong inhibition effects of TSM on the CDOM spectral properties in the short bands. The research results can provide theoretical basis for characteristic waveband selection, the application scope of water component concentration inversion algorithm and the waveband setting for case 2 water remote sensing.

18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(1): 137-41, 2010 Jan.
Article in Chinese | MEDLINE | ID: mdl-20302100

ABSTRACT

The complicated compositions of Case II waters result in the complex properties of spectral curves. The present paper analyzed the in situ measurements data of spectral curves, and further realized the relationships between the properties of spectral curves and suspended sediment concentration. The study found that the max peak of spectral curves was moving to the direction of shortwavelength as increasing suspended sediment concentration, namely the blue shift of wavelength; the area enclosed by spectral curve and coordinate axis in the range of sensitive bands had preferably linear relationship with the suspended sediment concentration (curve area model); the trapezoidal area model which was an approximation of curve area model could also excellently reflect those relationships, and be greatly suitable for multi-spectral satellite imagery retrieval such as LandSat/TM, MODIS and so on. The inversion results of trapezoidal area model for LandSat/TM imagery on October 27, 2003 in Taihu Lake showed that the suspended sediment concentration ranged from 30 to 80 mg x L(-1), the distribution pattern was higher in the west, south and central lake and lower in the east lake; compared with the in situ measurements in the regions, and the relative error of retrieval model was 6.035%.

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