How can we calculate the residual currents from the time series current data at a point. pl. explain?

Residual current is the average over a certain period of time, for example one tidal cycle. Let's say that you want the residual over a semi-diurnal tidal cycle, you can either (1) apply a lowpass filter to your time series to remove fluctuations at semi diurnal and higher frequencies; (2) obtain residuals through a least squares fit to semi-diurnal (M2) harmonic (in this case the residual would be the difference between observations and the model); (3) you can also interpolate your data at a small time interval (e.g. 1 min) over the complete tidal cycle (12h25) and simply compute the average. For examples, check Garel, E. and Ó. Ferreira. 2013. Fortnightly Changes in Water Transport Direction Across the Mouth of a Narrow Estuary. Estuaries and coasts 36: 286-299, and references therein.

I highly recommend the FORTRAN seen his power despite the high complexity of calculations and especially considering its simplicity in programming. The scientist need to focus on the scientific problem, not solve more complicated syntax errors that the problem itself!

A simple method for the determination of residual currents is vector addition for any chosen time cycle.

I think you can try with Mike 21 Tool Box. There is an option for Current analysis. Hope this ll help.

thanks 

https://books.google.com.tr/books?id=oeTFyli0aSIC&pg=PA150&lpg=PA150&dq=residual+currents+from+the+time+series+current+data+at+a+point&source=bl&ots=1h13AZw7KD&sig=tZ_VEkaoYA1-_sJUsuMKksCjIpk&hl=tr&sa=X&ved=0ahUKEwjUlZLtq-3XAhXHPBQKHZMxAH8Q6AEIMjAC#v=onepage&q=residual%20currents%20from%20the%20time%20series%20current%20data%20at%20a%20point&f=false

https://www.researchgate.net/post/Could_you_suggest_a_software_to_plot_current_speed_and_direction_patterns

hi

this link can help you

https://journals.ametsoc.org/doi/pdf/10.1175/1520-0485%281983%29013%3C1307%3AWITIRC%3E2.0.CO%3B2