Ship wake’s properties（e.g.microwave property

thermal infrared property

acoustic property

underwater optical scattering property of wake bubbles） have been extensively studied to monitor surface ship through the ages. However

there were few researches on above-water spectral features of ship wake

especially features with submerged bubbles.With the increase of the resolution of spaceborne optical sensor

measurement for ship wakes by optical remote sensing is feasible.The physical features and Apparent Optical Properties（AOPs） of ship wakes with bubbles was measured in situ

and how bubbles would affect AOPs of seawater in Case-Ⅱ waters

such as normalized water-leaving radiance and remote sensing reflectance

were analyzed in quantity.By comparing remote sensing reflectance of wake seawater containing bubbles with radiance resolution of ASTER VNIR radiometer

we can find that it is feasible to detect ship wakes containing bubbles by spaceborne optical sensors.In this paper

the main research domestic and abroad was introduced systematically.In accordance with the phenomenon in experiment of optical properties of sea water caused by bubbles

the influence of bubbles in wakes on optical properties caused by varieties of water bodies and environment（e.g.solar altitude angle

wind speed and cloud cover）

and quantificational evaluation of validity of wakes with bubbles based on satellite optical sensor were investigated.These works may provide some theoretical foundations for capturing the information of ship wakes from spaceborne optical sensors.Observations prove that ship wakes with bubbles can change AOPs of seawater in both the magnitude or spectral shape over the visible and infrared wave bands

and the color of water becomes greener because of wakes bubbles.And the bubbles’ concentration and reflectance increased with the distance from the observation position in wake to the target ship geting shorter.During the experiments

we found that the length of target ship wakes with bubbles exceeded 1km

and the width was about 40m.The concentration of bubbles in wakes became higher as the distance between observation point and target ship shortened.Therefore

the reflectance also enhanced.We observed another ship whose speed equaled to the target ship and tonnage was 2000t heavier than the target ship.Although we only took visual observation because of the limited experiment condition

we found that the length and width of its wake with bubbles were greater than that of target ship;therefore

we believe that the screw propeller can generate more bubbles as ship is heavier and faster.And the bubbles in wake are able to last a longer time when the screw propeller is located in deeper water and the time interval of bubbles rising to surface is longer.The changing of AOPs caused by the wake with bubbles will be much more distinct and last a longer time.At the same time

in Case-Ⅱ waters

the variations of seawater AOPs caused by the introduction of bubbles were not very clearly because the high concentration of suspended particles may increase the backscattering.In comparison

the variation of water color affected by ship wakes weakened when water was more turbid.Although the information of wake with bubbles obtained by optical sensor varied with wave bands

the variance of seawater spectrum caused by wake bubbles can be extracted more easily with the improvement of the radiance and spatial resolution of modern optical sensor（the quantification grade of optical sensors carried by QuickBird and IKONOS arrive at 11bits

and the spatial resolution is 0.6m

1m respectively）.Wind speed was less than 10m·s-1 and the sea condition was good when we took experiments.The effect of the roughness of sea surface on experiment did not completely emerge.In order to fully analyze how marine environment affects AOPs of wake seawater with bubbles

more experiments are needed in other wind speed and sea condition.Meanwhile

we need to take more experiments to measure vessels of different size and speed.We wish to summarize the rules of AOPs of wake seawater comparing with background seawater by means of combining satellite remote sensing information with experiment data.Finally

we may achieve our goals of monitoring and identifing ships in large-scale sea area by using spaceborne optical sensor.