Ocean has 4 types :

Purvi thaat
Bhairav th
Kalingada ang
Marwa ang

https://www.youtube.com/watch?v=3d0b46Avi80 - Pt Jasraj - Bhairav th

https://www.youtube.com/watch?v=th7ZX8Z0ym0 - (Purvi Thaat) by Pt.C.R.Vyas

( Gouri )

Jasraj´s drut sounds a little bit like Kalingada and Rewa ( Purvi ang ) to me , since he doesn´t use the emphasis on the mandra Ni .
However the nyaas on Ga might make it suitable for a dusk melody , or even bring out Gauri-ang ... ( I might be wrong )
Btw , swarganga says that for Bhairav thaat Gauri m is vadi whereas Ocean says that r is the vadi . Tanarang doesn´t specify vadi but most of his phrases end on Ga . Pranavparijat´s vadi is Sa ; for them S , G , P and N get nyAs .

Since Gauri ( Bhairav thaat and/or Kalingada ang ) and Kalingada are rather difficult to separate for me ( except when the mandra Ni is emphazied or when some Shri-ang is being borrowed in Gauri ) I´ll paste an interesting comment from Quora :

( Ramkrishna Das )
" these raags have the same notes and same tones when shuddhaa gauri is taken into account. phrases CAN differentiate the raags u have mentioned

bhairav:

GMd~~~~, d~MP, GM~~r~~~, Sd’~~~d’d’d’—S—-N’d’~S, N’SGMd~~~d-P, MPGMd~~~Nd—MP—, while playing and singing gamare there is an invisible trace of komal ga in bhairav, sometimes and rarely komal ni is used as a vivaadi swar to give an aesthetic touch to the raag e.g. GMd~~~P—-ndP—dndP—-d~MP GM~~r.

tonal movement in all octaves is done uniformly.

KAALINGDAA

SrSN’S—-, S— Sr GrG—, GrGM GrS—- N’SrS N’N’S—, SrGMGM—- PMGrGMG—- PdPd- MPMP— GMGM—- GrG SrS— SrSN’S—-.

SrGM PM PdP—— PdPd—NS*NS*——S*NdP MPdNS*—— S*NS*r* S*NS—- S*NdP— NNdP PMPdP—-PMGr GrG——GGrS—SN’S— SN’d’N’S—-

tonal movement emphasizes moderately MORE towards taar saa being a morning melody. GrG rGrM~G might also be employed sparingly as it has gaud hidden in the name of kaalingdaa or kalinga gaud. shuddha ma has a role to play being the part of gaud.

GAURI/ SHUDDHAA GAURI

SrS— N’S-N’d’N’—-SrS - Sr GrG— GrG rGrM~G—-GrGM GrSS—N’SN’d’N’—

SrGM rMGr—GrS—-SrS SP— PMP PMGr GM PMGM—-

PdMP —GMPdP —Pd MPNN—S*——, S*NS*- NdN— dPd— PMP— MGM—- GrG— rSr— SN’S— N’d’N’—- P’d’N’d’P’—-N’N’—S—-.

tonal movements in the first half of the octave is more appreciated as gauri is an evening melody. gauri can employ repetition of notes pa ma ga in the decreasing order. "

For Gauri , he uses lots of Nyaas for Ga and ma , less for Pa and re .

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Apparently deviating from others ( ? ) Pt Vasantrao Deshpande´s Bhairav thaat prakar uses sometimes uses `NrG which sounds like a Purvi influence to me .

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Smt. Manjari Asnare Kalkar´s Purvi thaat Gauri drut has the mandra Ni on sam , which makes it transparent for me .

https://www.youtube.com/watch?v=nTr03q3Ns5M

https://www.youtube.com/watch?v=mS4V2dWa2Ho - Pta. Shubhada Paradkar - Bhairav Thaat

https://www.youtube.com/watch?v=YS45OGma_LY - Purvi th - Dr.Gauri Moghe " Devi Durge -- sthayi has mandra Ni .

Ocean has a clip of Ratanjankar for his Marwa th - Gauri , but it is mislabelled since the clip shows Purvi th .

Anyway , here s Ratanj. ´s " Do madhyam ki Gauri " ( dvi-madhyam ) :

https://www.youtube.com/watch?v=CM-D8OMrcr8

Btw , at Ocean the Gauri prakar with 2 ma is of Kalingada-ang . ( Clip by Ginde ) .

QUOTE
> Smt. Manjari Asnare Kalkar´s Purvi thaat Gauri drut has the mandra Ni on sam , which makes it transparent for me .
>
> https://www.youtube.com/watch?v=nTr03q3Ns5M

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" Surat mohani dekhi pritama ki "

Same drut by Smt. Manjusha Patil Kulkarni , with some spice .

https://www.youtube.com/watch?v=HykNxahfZQ0

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QUOTE " https://www.youtube.com/watch?v=YS45OGma_LY - Purvi th - Dr.Gauri Moghe " Devi Durge -- sthayi has mandra Ni . "

Here are 2 other clips with better intonation :

https://www.youtube.com/watch?v=M7Smic3iDXQ - Dr Ashw Bhide Deshpande

https://www.youtube.com/watch?v=NL-e_1kaywc - Aditya Vijay Bhandari

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https://www.youtube.com/watch?v=_ql2p3KoJoY - Kedar Bodas´ drut has some dynamism . " Aisi aisi " ?