The first two events are ongoing and have been mentioned on this blog en passant; the last two are coming up.
Gibraltar (Gibtel) is down to the last round, and after 9 of 10 rounds there's a four-way tie for first between Movsesian, Vallejo Pons, Adams and Gustafsson, each with 7 points. Fourteen(!) players are half a point behind, including Bacrot and Kamsky. (Tournament site here.)
In Moscow 5 (of 9) rounds are over, and Dmitry Andreikin leads this prestigious open with 4½ points, half a point ahead of fourteen players (again 14!) including stars like Motylev, Bologan, Rublevsky, Bu Xiangzhi and Bareev. (Tournament site here [in Russian] or here [in English].)
The Aeroflot Open begins shortly after Moscow concludes, running from February 8 to 19. According to TWIC, the field is scheduled to include such players as Bacrot, Bu Xiangzhi, Cheparinov, Motylev, Khalifman, Naiditsch, Nepomniatchi, Sargissian, Sasikiran, Smirin, Timofeev, Vachier-Lagrave, Van Wely and Zvjaginsev. (Tournament site here.)
Finally, the biggie: Linares. It will run from February 12 to 25 in Linares, Spain (and only there: no halves in Morelia or Dubai), and will feature Topalov, Aronian, Gelfand, Grischuk, Gashimov and local player Vallejo Pons in a double round-robin. (Tournament site here.) Surprisingly, TWIC reports that this is Gashimov's first super-GM event, but this it true only in a very narrow sense. Maybe he hasn't played here or in Dortmund, but the Grand Prix events last year were essentially super-GM tournaments. Here he'll only have players in the upper 2700s (except for Vallejo), but that's not that much of a break from a field with high and low 2700s, so I think he'll do fine. (I doubt he'll win the event, but I don't think he'll do badly or be anywhere near outclassed. He should fit right in.)