Year: 2017
Type: article
Abstract: Recurrent and significant Sargassum beaching events in the Caribbean Sea (CS) have caused serious environmental and economic problems, calling for a long‐term prediction capacity of Sargassum blooms. Here we present predictions based on a hindcast of 2000–2016 observations from Moderate Resolution Imaging Spectroradiometer (MODIS), which showed Sargassum abundance in the CS and the Central West Atlantic (CWA), as well as connectivity between the two regions with time lags. This information was used to derive bloom and nonbloom probability matrices for each 1° square in the CS for the months of May–August, predicted from bloom conditions in a hotspot region in the CWA in February. A suite of standard statistical measures were used to gauge the prediction accuracy, among which the user's accuracy and kappa statistics showed high fidelity of the probability maps in predicting both blooms and nonblooms in the eastern CS with several months of lead time, with overall accuracy often exceeding 80%. The bloom probability maps from this hindcast analysis will provide early warnings to better study Sargassum blooms and prepare for beaching events near the study region. This approach may also be extendable to many other regions around the world that face similar challenges and opportunities of macroalgal blooms and beaching events.
Source: Geophysical Research Letters
DOI: 10.1002/2017gl072932
Authors: Mengqiu Wang, Chuanmin Hu
Institution: University of South Florida St. Petersburg
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: bronze
Awards: THIS PROPOSAL ADDRESSES TWO TOPICS OF THE NNH15ZDA001N-OBB RFP: TOPIC 2.1 (OCEAN ECOLOGY ESPECIALLY TO PREPARE FOR THE PACE MISSION) AND TOPIC 2.4 (SUCCESSOR STUDIES OF PREVIOUSLY OBB-FUNDED PROJECTS).PELAGIC SARGASSUM MACROALGAE SERVE AS AN ECOLOGICALLY IMPORTANT HABITAT FOR MANY MARINE ANIMALS WHILE EXCESSIVE SARGASSUM BEACHING HAS BECOME AN INCREASING NUISANCE SINCE 2011. SARGASSUM MAY ALSO AFFECT OCEAN'S BIOGEOCHEMISTRY THROUGH MODULATING NUTRIENT CYCLES AND RELEASING COLORED DISSOLVED ORGANIC MATTER. HOWEVER TO DATE EXCEPT FOR A HANDFUL OF STUDIES OUR KNOWLEDGE IN THESE AREAS IS ONLY NEXT TO NIL.PREVIOUS MAPPING EFFORTS BASED MAINLY ON MERIS MEASUREMENTS SHOWED BLOOM PATTERNS IN THE INTRA-AMERICAS SEA (IAS). HOWEVER THESE PRELIMINARY RESULTS ARE SUBJECT TO REVISIT BECAUSE OF THE SIMPLE METHODS USED IN THE ESTIMATES AND BECAUSE OF LACK OF MERIS COVERAGE AFTER APRIL 2012. FURTHERMORE THE UNPRECEDENTED SARGASSUM BEACHING EVENTS IN THE CARIBBEAN IN 2015 CALLS FOR A BETTERUNDERSTANDING OF ITS LONG-TERM TREND IN BOTH DISTRIBUTION AND ABUNDANCE.TWO PROJECTS HAVE BEEN FUNDED BY THE NASA OBB PROGRAM (NNX13AD08G NNX14AL98G) TO ASSESS THE DEEPWATER HORIZON OIL SPILL IN THE NE GULF OF MEXICO (GOM) AND TO PROVIDE NEAR REAL-TIME IMAGERY TO HELP TRACK SARGASSUM RESPECTIVELY. THESE FUNDED PROJECTS LED TO GROUND-BREAKING WORK OF USING LANDSAT AND MODIS TO MAP SARGASSUM WITH SIGNIFICANT PROGRESS BEING MADE TO DATE FOR EXAMPLE THE DISCOVERY OF THE GREAT ATLANTIC SARGASSUM BELT. ONE CONCLUSION FROM THESE RESULTS IS THAT SARGASSUM ABUNDANCE AND BIOMASS MAY HAVE BEEN SIGNIFICANTLY UNDERESTIMATED IN THE PAST.BASED ON THESE PRELIMINARY RESULTS THE ULTIMATE GOAL IS TWO-FOLD: TO STUDY SARGASSUM DISTRIBUTION AND ABUNDANCE AS WELL AS TO UNDERSTAND THE DRIVING FACTORS USING EXISTING SENSORS AND ENVIRONMENTAL VARIABLES AND TO DESIGN AND TEST ALGORITHMS SPECIFICALLY FOR PACE AND EXISTING MULTI-BAND SENSORS. SPECIFICALLY THE PROJECT HAS THE FOLLOWING OBJECTIVES:1) DESIGN IMPLEMENT AND TEST PACE-COMPATIBLE ALGORITHMS TO DETECT AND QUANTIFY SARGASSUM FROM WHICH ALGORITHMS TO USE EXISTING MULTI-BAND SENSORS ARE ALSO IMPROVED2) PROVIDE THE BEST ESTIMATES OF TOTAL SARGASSUM BIOMASS (AND PIGMENTS AND C N P FE) AND DISTRIBUTIONS THEIR SEASONALITY INTERANNUAL VARIABILITY AND LONG-TERM TREND WITH UNCERTAINTY ESTIMATES3) DETERMINE DOMINATE ENVIRONMENTAL FACTORS (NUTRIENT AVAILABILITY WEATHER FLUCTUATIONS OCEAN MIXING AND CIRCULATION ETC) THAT DRIVE THE INTER-ANNUAL VARIABILITY AND LONG-TERM TREND IN THE DISTRIBUTION PATTERNS4) DOCUMENT HOW SARGASSUM POPULATIONS ARE CONNECTED BETWEEN THE GOM TROPICAL ATLANTIC AND OTHER REGIONS OF THE IAS5) IMPROVE EXISTING DATA PRODUCTS IN THE CURRENT SARGASSUM WATCH SYSTEM TO BETTER SERVE THE COMMUNITY AND PROVIDE MANAGEMENT DECISION SUPPORT.THE PROJECT WILL BE CONDUCTED THROUGH MULTI-SENSOR REMOTE SENSING CAREFULLY DESIGNED FIELDWORK LABORATORY MEASUREMENTS AND INTEGRATED DATA ANALYSIS BY AN INTER-DISCIPLINARY TEAM. THE PROJECT WILL LEVERAGE ON CURRENTLY FUNDED GOMRI CRUISE SURVEYS AND CRUISE SURVEYS BY OUR PARTNERS TO SAVE SHIP COST.THE PROJECT WILL MAKE SIGNIFICANT CONTRIBUTIONS TO NASA GOALS AND IN PARTICULAR TO THIS RFP FOR TWO REASONS: 1) IT IS PERFECTLY SUITABLE TO ADDRESS QUESTIONS SPECIFIED IN TOPIC 2.1 AS IT WILL NOT ONLY PROVIDE FOR THE FIRST TIME THE LONG-TERM TREND OF SARGASSUM ABUNDANCE BUT ALSO LEAD TO BETTER UNDERSTANDING OF THE ENVIRONMENTAL FACTORS DRIVING THE SHORT-TERM CHANGES AND LONG-TERM TREND.FURTHERMORE CURRENT SENSORS (MODIS AND LANDSAT) AND FUTURE SENSORS (PACE) ARE USED NOT ONLY FOR RESEARCH BUT ALSO TO BETTER INFORM MONITORING MANAGEMENT AND DECISION AND POLICY MAKERS. 2) IT IS BASED ON RESULTS FROM PREVIOUSLY OBB-FUNDED RESEARCH WHICH WILL MAKE SIGNIFICANT ADVANCEMENT FROM THE RESULTS OBTAINED TO DATE. THE PROJECT IS ALSO RELEVANT TO OTHER NASA THEMES FOR EXAMPLE ECOLOGICAL FORECASTING BIODIVERSITY AND APPLIED SCIENCE., MAXIMIZE MODIS POTENTIALS FOR NEAR REAL-TIME OCEAN APPLICATIONS THROUGH DEVELOPING AND REFINING NOVEL ALGORITHMS AND PRODUCTS EXCELLENT NEAR REAL-TIM, WE HAVE STARTED A PROGRAM TO APPLY THE NEXT GENERATION OF THE D ALESSIO MODEL TO THE INTERPRETATION OF PROTOPLANETARY DISKS CULLED FROM POPULATIONS OF DIFFERENT AGES AND EVOLUTIONARY STAGES WITH THE GOAL OF CHARACTERIZING THE CONDITIONS THAT DRIVE DISK EVOLUTION AND LEAD TO THE FORMATION OF PLANETS. OUR CODES ARE THE SUCCESSORS OF THE CODES THAT CALCULATE THE STRUCTURE AND EMISSION OF IRRADIATED ACCRETION DISKS WITH WHICH WE HAVE ALREADY MADE IMPORTANT DISCOVERIES SUCH AS THE IDENTIFICATION OF DISKS WITH GAPS AND THE FIRST FINDING OF WATER ICE. THE NEW MODELS CALCULATE THE STRUCTURE OF THE DUST AND OF THE GAS SEPARATELY BUT SELF-CONSISTENTLY AND INCLUDE SEVERAL ASPECTS THAT HAVE NOT BEEN FULLY TAKEN INTO ACCOUNT BEFORE: (A) VISCOUS DISSIPATION AS A HEATING AGENT OF THE GAS; (B) SOLUTION OF THE DISK STRUCTURE EQUATIONS TO GET SELF-CONSISTENT HYDROSTATIC STRUCTURES OF GAS AND DUST; (C) GAS ABSORPTION IN THE TRANSPORT OF HIGH ENERGY RADIATION IN ADDITION TO DUST; (D) DUST PROPERTIES (MINERALOGY SIZE DISTRIBUTIONS SUBLIMATION TEMPERATURES CONSISTENT WITH THE CHEMISTRY VERTICAL AND RADIAL DISTRIBUTION) INFERRED FROM THE MODELING OF THE SED AND/OR RESULTS OF NUMERICAL SIMULATIONS; (E) FLEXIBILITY IN THE CODE TO ALLOW FOR SURFACE DENSITY DISTRIBUTIONS OF GAS AND OF DUST INCLUDING RESULTS FROM NUMERICAL MODELS OF TURBULENT MRI-DRIVEN DISKS WITH RADIAL DRIFT AND TRAPPING OF DUST. HERE WE PROPOSE TO MODEL THE DISKS OF STARS STILL EMBEDDED IN THEIR INFALLING ENVELOPES AND TO INCLUDE SELF-CONSISTENTLY THE INTERACTION OF THE DISK AND THE ENVELOPE. WE WILL CALCULATE THE STRUCTURE OF THE DISK AROUND HL TAU AND IN PARTICULAR THE LOCATION OF THE CONDENSATION FRONTS OF VOLATILES FOR COMPARISON WITH OBSERVATIONS. OUR MODELING WILL PROVIDE MUCH INSIGHT INTO THE NATURE OF THE RADIAL SUBSTRUCTURE IN PROTOPLANETARY DISKS AND THE BEST REPRESENTATION OF THE EARLY SOLAR NEBULA.
OpenAlex ID: W2599014886